化简 (21 21:8:15)sin(2a+b)/sina-2cos(a+b)

化简 (21 21:8:15)sin(2a+b)/sina-2cos(a+b) 化简 √(2+cos2-sin^21) 注：这个是sin的平方1 在Rt△ABC中,角C=90°,求证sin^2A+sin^2B=1,并利用上式求sin^21°+sin^22°+sin^32°+……+sin^289°的值 sin^8X+cos^8X+4sin^2Xcos^2x-2sin^4xcos^4X(化简） 化简sin(-2x) sin^2(-a)化简 化简sin^2α+sin^2β+2sinαsinβcos(α+β) 化简sin(α+β)+sin(α-β)+2sinαsin(3π/2-β)= 计算,sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8) 化简sin(α+β)-2sinαsinβ/2sinαsinβ+cos(α+β) 化简4sin派/8*cos派/8*(cos^2派/8-sin^2派/8) 化简：2sin(πx/8+π/4)+sin(-πx/8+π/4)= 化简sin^(a-30°)+sin^(a+30°)-sin^a化简sin^2(a-30°)+sin^2(a+30°)-sin^2a 化简 cos^2(x)*sin^2(x)-sin^2(x) 化简 cos^(2)(x)*sin^(2)(x)-sin^(2)(x) 化简sin^4x-sin^2x+cos^2x 化简:sin^4 x-sin^2 x+cos^2 x 化简:sin(-a)cos(2π+a)sin(-a-π)