Bài tập phương trình lượng giác | Môn toán cao cấp
Đường tròn lượng giác ▶ Là đường tròn có tâm O trong mặt phẳng Oxy và có bán kính R = 1. ▶ A(1;0) là điểm gốc của đường tròn lượng giác.Chiều dương là chiều ngược chiều kim đồng hồ. Chiều âm là chiều cùng chiều kim đồng hồ.Tài liệu giúp bạn tham khảo, ôn tập và đạt kết quả cao. Mời bạn đọc đón xem !
Môn: Toán Cao Cấp (KTHCM)
Trường: Đại học Kinh tế Thành phố Hồ Chí Minh
Thông tin:
Tác giả:
Preview text:
lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE Chuyên Á 1
PH¯¡NG TRÌNH L¯þNG GIÁC
XÁC ĐÞNH GIÁ TRÞ L¯þNG GIÁC lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC CĂA MÞT G C HAY CUNG L¯þNG GIÁC ✓
1 . Đ°ßng tròn l°ÿng giác
Là đ°ờng tròn có t m O trong mặt phẳng Oxy v c bÆn k nh R 1 . Aø 1 ;0 ù
là điểm gốc của đ°ờng tròn l°ÿng giác.
Chiều d°¡ng là chiều ng°ÿc chiều kim đồng hồ.
Chiều âm là chiều cùng chiều kim đồng hồ. 2. G
iá trß l°ÿng giác Cho cung AM sin OK
Tung độ của điểm M . Cos = cos OH
Hoành độ của điểm M . sin tan AT t At tại T ) c
(KØo d i OM cắt tiếp tuyến ’ os cos cot 0 ; 1 ) s
(KØo d i OM cắt tiếp tuyến ’
s Bs tại S , với ø ù in B B 2 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
CÔNG THþC L¯þNG GIÁC ✓ 1. Hß thÿc c¢ bÁn 1 tan2 a 12 tana 1 sin2 a cos2 a 1cos a tan .cota a 1cota 1 cot2 a 12 cota 1 sin atana tana
sina sina tan cosa a cota
cosa cosa cot .sina
a cosa sina 2. Cung liŒn k¿t 3. C ng thÿc cßng
sin(a b ) sin cosa b sin cosb a cos( a) cosa sin( a) sina sin( a) sina
cos(a b) cos cosa b sin sina cos( a) cosa tan( a) tana b tan( a) tana cot( a) cota cot( a) cota 4 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE ö ö ö ö
tan(a b ) tana tanb
sin÷ a÷ cosa ø 2
sin÷ a÷ cosa ø 2 1 tan .tana b ø ø ö ö ö ö cot(a b )
cos÷ a÷ sina ø cos÷ a÷ sina ø 2 ø ö ö 2 ø ö ö
tan÷ a÷ cota ø 2
`p dāng c ng thÿc cßng ta °ÿc tan÷ a÷ cota ø 2 ø ø ö ö ö ö ö ö
sinx cosx 2 sin÷x ÷
cot÷ a÷ tana ø 2 ø cot÷ a÷ tana ø 2 ø 4 ø ö ø ö
cosx sinx 2 cos÷x ÷ ø 4 ø … 4. Cung liŒn k¿t
5. C ng thÿc nhân ôi
sin2a 2sin cosa a sin( a) sina sinøa ù sina cos2 a–sin2 a cos( a) cosa cosøa ù tan( a) tana
cos2a 1 2sin2 a cot( a) cota cosa tanøa ù 2cos2 a 1 tana cotøa ù tan2a 2tana2 cota 1 tan a
sin÷ a÷ cosa cosö÷
aö÷ sina ö ö cot2a 1 1 tan2 a tan2a ø 2 ø ø 2 ø 2tana
tan÷ a÷ cota cotö÷
aö÷ tana ö ö ø 2 ø ø 2 ø 6.C ng thÿc h¿ b¿c
sinøa k .2 ù sina cosøa k .2 ù cosa *sin2 a
1 cos2a 1cos2a 2sin2 a 2
tanøa k ù tana cotøa k ù cota *cos2 a
1 cos2a 1cos2a 2cos2 a 2 *tan2 a 1 cos2a 1 cos2a lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
7. C ng thÿc bi¿n t ch th nh táng *cos
8.C ng thÿc bi¿n táng th nh t ch
.cosa b ù ûcos(a b ) cos(a b ù)û
*cosa cosb 2cos÷a b ö÷cosö÷a b ù ö÷ ö *sin .sina b 1 ûcos(a b ) ø 2 ø ø 2 ø cos(a b ù)û cosa cosb
2sinö÷a b ö÷sinö÷a b *sin .cosa
b ùûsin(a b ) sin(a b ù)û 2 ö÷ ø 2 ø ø 2 ø ù *cos .sina b 1 ûsin(a b ) ö sin(a b ù)û 2
*sina sinb 2sin÷a b ö÷cosö÷a b ö÷ ø 2 ø ø 2 ø
sina sinb 2cosö÷a b ö÷sinö÷a b ö÷ ø 2 ø ø 2 ø *tana tanb sin(a b ) cos cosa b
Ghi chØp: ........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... VÂN ĐÀ 1
PH¯¡NG TRÌNH L¯þNG GIÁC C¡ BÀN ✓ A. PH¯¡NG PH`P 6 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE 1. radian ù u v k2 æo ùu v k 3600 hoặc sinu sinv ú 0 0 ,k
sinu sinv úû v k2 ,k
úûu 180 v k360 æo ùu u radian ù u v k2
cosu cosv úû v k2 ,k u v k 3600
2. hoặc cosu cosv ú 0 ,k úûu v k360
radian tanu tanv
æo tanu tanv u v
3. u v k , k
hoặc k 1800, k
radian cotu cotv
æo cotu cotv u v k
4. u v k , k hoặc 1800, k radian
ù x arcsinm k 2 sinx m úû
arcsinm k 2 ,k ĐẶC x BIÞT radian sinu
ù x arccosm k 2 1 u cosx m úû
arccosm k 2 ,k k2 x 2 radian sinu
tanx m x arctanm k , k 1 radian u k2
cotx m x arccotm k , k 2 sinu 0 u k cosu 1 u k2 cosu 1 u k2 lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC cosu 5. 0 u k 2 6. 7. 8.
Ghi chép bá sung
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
..................................................................................................................................................................
.................................................................................................................................................................. B. VÍ DĀ ö ö 8 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE
Ví dā 1. Giải ph°¡ng trình sin÷x ÷ sin 2 . ø 2 ø 5 Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 2. Giải ph°¡ng trình sinøx 30 ù 0 sin200 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 3. Giải ph°¡ng trình sinxøcosx 2ù 0 Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 4. Giải ph°¡ng trình 2sinx 1. Lßi giÁi lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 5. Giải ph°¡ng trình sin÷x ÷ 1. ø 5 ø Lßi giÁi
.................................................................................................................................................................. .....
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 6. Giải ph°¡ng trình 2sin÷x ÷ 2 0 . ø 6 ø Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 7. Giải ph°¡ng trình 2sinøx 60 ù 0 3 0 . 10 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 8. Giải ph°¡ng trình sin3x cos÷öø x 3 ö÷ø . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 9. Giải ph°¡ng trình cos 2÷öø x ö÷ø sin÷øö x 4 öø÷ . 5 Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 10. Giải ph°¡ng trình 5sinx 1 . lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 11. Giải ph°¡ng trình sinøx 2ù . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 12. Giải ph°¡ng trình cos÷x 2 ö÷ cos . ö ø 5 ø 7 Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 13. Giải ph°¡ng trình cosøx 40 ù 0 cos100 . Lßi giÁi 12 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 14. Giải ph°¡ng trình 2cosx 1 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 15. Giải ph°¡ng trình cos÷x ÷ 1 . ø 8 ø Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 16. Giải ph°¡ng tr nh 2cos÷x ÷ 3 0 . ø 6 ø Lßi giÁi
....................................................................................................................................................................... lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 17. Giải ph°¡ng trình 2cosøx 30 ù 0 2 0 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 18. Giải ph°¡ng trình 3cosx 3 0 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 19. Giải ph°¡ng trình 5cosø2x 1ù 30 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... 14 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE
Ví dā 20. Giải ph°¡ng trình tan÷x 3 ö÷ tan . ö ø 4 ø 7 Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 21. Giải ph°¡ng trình tanøx 48 ù 0 tan250 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 22. Giải ph°¡ng trình tanx 3 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 23. Giải ph°¡ng trình tan÷ x÷ cot . ø 6 ø 6 lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 24. Giải ph°¡ng trình tanøx 30 ù 0 10. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 25. Giải ph°¡ng trình 2tanx 5 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 26. Giải ph°¡ng trình cot÷x ÷ cot . ø 8 ø 5 Lßi giÁi
....................................................................................................................................................................... 16 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 27. Giải ph°¡ng trình cotøx 28 ù 0 cot120 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 28. Giải ph°¡ng trình 3cotx 3 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ö ö
Ví dā 29. Giải ph°¡ng trình cot÷x ÷ 1 0 . ø 6 ø Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
Ví dā 30. Giải ph°¡ng trình cot 2ø x 20 ù o 3 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 31. Giải ph°¡ng trình 3cotx 5 0 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 32. Giải ph°¡ng trình cosx sinx 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 33. Giải ph°¡ng trình 3sinx cosx 0. Lßi giÁi 18 lOMoAR cPSD| 49519085 Tr°ờng THPT MARIE CURIE
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 34. Giải ph°¡ng trình 3cosx sinx 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 35. Giải ph°¡ng trình sin2x sin2 cosx x 0. Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 36. Giải ph°¡ng trình cosx 2sin2 x 0 . 2 Lßi giÁi
.......................................................................................................................................................................
....................................................................................................................................................................... lOMoAR cPSD| 49519085
ChuyŒn đề 1: L¯þNG GIÁC
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 37. Giải ph°¡ng trình sin3x sinx 0 . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
Ví dā 38. Giải ph°¡ng trình cos4x sinx . Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... ù ù
Ví dā 39. Ph°¡ng trình 2cos2 x 1 0 có bao nhiêu nghiệm trên đoạn ú 3 ; ú . û 2 2 û Lßi giÁi
.......................................................................................................................................................................
.......................................................................................................................................................................
.......................................................................................................................................................................
....................................................................................................................................................................... 20