求sin^2 40°+cos^2 10°-sin40°sin80°的值.

求sin^2 40°+cos^2 10°-sin40°sin80°的值. 求sin^2 40°+cos^2 10°+sin40°cos10° 求(sin^2)15°(cos^2)15° 已知sinα-2cosα=10求(sinα-4cosα)/(5sinα+2cosα) 求2sin(-1110°)-sin960°+根号2cos(-225°)-cos(-210°) 求sin 135°+cos平方 150°+2sin210°cos平方 225° 求sin^2 （10°）+cos^2(40°）+（sin10°）*（cos40°）的值 sin^2 30°+cos()=1 利用公式求下列三角函数値:(l).cos(-420°);(2).sin(-7/6ㅠ);(3).sin(-1300°);(4).cos(-79/6&(4) cos(-79/6ㅠ) sin^2(10)+cos^2(40)+sin10cos40 己知sin^2θ=sinα cosα 求cos2θ=2sin(45°-α) cos(45°+α) 急!~~ 求下列三角函数sin(a+180°)cos(-a)sin(-a-180°) 2.sin∧3(-a)cos(2pai+a)tan(-a-pai) 1.sin的三次方(-α)cos(2π+α)tan(-α-π)2.cos(180°+α)sin(α+360°)/sin(-α-180°)cos(-180°-α)3.sin(2π-α)cos(π+α)cos(π/2+α)sin(9π/2+α)/cos(π-α)sin(3π-α)sin(-π-α)4.已知sinα=-3/5,求cosα,tanα的值5.已知tanα=-根号下3,求 sin^2 80°为什么等于 cos^2 10°? 求下列各式的值：（1）sin(70°+a)cos(10°+a)-cos(70°+a)sin(170°-a)（2）cos(36°+x)cos(54°-x)-sin(36°+x)sin(54°-x) (cos^2 10°-cos^2 80°)+sin^2 20° 求角的数值 sin 32° = cos ( 66° - θ/2 ) 求角的数值sin 32° = cos ( 66° - θ/2 ) tan=-2,求sin,cos