求(sin^2)15°(cos^2)15°

求(sin^2)15°(cos^2)15° (cos^2)15°+(sin^2)15°等于多少 cos^2 15°-sin^2 15°的值 cos^2 15°-sin^2 15°= cos^2 15°—sin^2 15°＝? (cos^2)15°-(sin^2)15等于多少 化简:sin^2(75°)*cos^2(15°)-cos^2(75°)*sin^2(15°) 化简:sin^2(75°)*cos^2(15°)-cos^2(75°)*sin^2(15°) 求cos^15°+sin^15°的值 化简：cos²（α+15°）+sin²（α-75°）+sin（α+180）*cos（α-180）已知tan（α+π/4)=2,求cos2α+3sin²α+tan2α的值 tan=-2,求sin,cos 求不定积分sin^2cos^4 cos=1/2,求sin y=sin@/2-cos@求值域 sinα=-2cosα,求sin^2α-3sinαcosα+1 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 化简1：cos(15°-a)sin15°-sin(165°+a)cos(-15°)2：根号下cos(60°-a)-sin(60°-a) 2sinθ = cosθ + 1,怎么求sin