求(sin^2)15°(cos^2)15°
(cos^2)15°+(sin^2)15°等于多少
(cos^2)15°-(sin^2)15等于多少
求cos^15°+sin^15°的值
求2sin(-1110°)-sin960°+根号2cos(-225°)-cos(-210°)
sinΘ-2cosΘ=0,Θ属于(0.,90°),求sinΘ、cosΘ的值.
已知 sin a,sin 2x ,cos a 成等差数列,sin a ,sin x ,cos a 成等比数列,求cos
sin(x+105°)cos(x-15°)-cos(x+105°)sin求化简
化简cos^2(a+15)+sin^2(a-15))+sin(a+180)cos(a-180)
化简~cos^2(a+15)+sin^2(a-15)+sin(a+180)cos(a-180)
sinα=-2cosα,求sin^2α-3sinαcosα+1
已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x
三角函数题2sin^2α-cos^α+sinα*cosα-6sinα+3cosα=0 求(2cos^α+2sinαcos