(1)sin765(2)cos(-1020)(3)tan(97π/6)(4)cot(-39π/6)(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)要用诱导公式!
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![(1)sin765(2)cos(-1020)(3)tan(97π/6)(4)cot(-39π/6)(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)要用诱导公式!](/uploads/image/z/5211692-44-2.jpg?t=%EF%BC%881%EF%BC%89sin765%EF%BC%882%EF%BC%89cos%28-1020%EF%BC%89%EF%BC%883%EF%BC%89tan%2897%CF%80%2F6%EF%BC%89%EF%BC%884%EF%BC%89cot%28-39%CF%80%2F6%EF%BC%89%EF%BC%885%EF%BC%89sin%28-120%29tan%28-120%29%2Bcos%28-135%29cot%28420%29%2Bsin%283%CF%80%2F2%EF%BC%89%E8%A6%81%E7%94%A8%E8%AF%B1%E5%AF%BC%E5%85%AC%E5%BC%8F%EF%BC%81)
(1)sin765(2)cos(-1020)(3)tan(97π/6)(4)cot(-39π/6)(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)要用诱导公式!
(1)sin765
(2)cos(-1020)
(3)tan(97π/6)
(4)cot(-39π/6)
(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)
要用诱导公式!
(1)sin765(2)cos(-1020)(3)tan(97π/6)(4)cot(-39π/6)(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)要用诱导公式!
sin764=sin(360*2+45)=sin45=√2/2
cos(-1020)=cos(360*3-1020)=cos60=1/2
tan(97π/6=tan(96π/6+π/6)=tan(π/6)=√3/3
cot(-39π/6)=cot(42π/6-39π/6)=cot(2/π)=0
sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)=
-sin(-120+180)tan(180-120)-cos(180-135)cot(420-360)-1
=-sin60tan60-cos45tan60-1
=-3/2-√6/2
sin765=sin(720+45)=sin45=√2/2
cos(-1020)=cos1020=cos(3*360+40)=cos40
tan(97π/6)=tan(16π+π/6)=tanπ/6=√3/3
cot(-39π/6)=-cot(39π/6)=-cot(6π+π/2)=-cot(π/2)=0
sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)
=(-sin60)tan60+(-cos45)cot60-1
=-√3/2*√3-√2/2*√3/3-1
=-3/2-√6/2
(1)sin765=sin(720+45)=sin45=√2/2
(2)cos(-1020)=cos(-1080+60)=cos60`=1/2
(3)tan(97π/6)=tan(96π/6+π/6)=tan(π/6)=√3/3
(4)cot(-39π/6)=cot(-48π/6+9π/6)=cot3π/2=0
(5)sin(-120)tan(-120)+cos(-...
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(1)sin765=sin(720+45)=sin45=√2/2
(2)cos(-1020)=cos(-1080+60)=cos60`=1/2
(3)tan(97π/6)=tan(96π/6+π/6)=tan(π/6)=√3/3
(4)cot(-39π/6)=cot(-48π/6+9π/6)=cot3π/2=0
(5)sin(-120)tan(-120)+cos(-135)cot(420)+sin(3π/2)
=(-sin120)(-tan120)+cos135cot(360+60)-1
=sin120tan120+cos135cot60-1
=sin(180-60)tan(180-60)+cos(180-45)√3/3-1
=sin60(-tan60)+(-cos45)*√3/3-1
=-3/2-√6/6-1
=-5/2-√6/6
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