求证 sinx(cos^2 2x-sin^2 2x) + 2cosx cos2x sin2x= sin 5x

求证sin（2x+y)/sinx-2cos(x+y)=siny/sinx 求证：sin(2x+y)/sinx-2cos(x+y)=siny/sinx 求证:Sin^2 x / (sinx-cosx) - (sin x + cos x)/(ta求证:Sin^2 x / (sinx-cosx) - (sin x + cos x)/(tan^2-1) = sin x + cos x 已知sinθ+cosθ=2sinx,sinθcosθ=sin²y,求证：4cos²2x=cos²2y 求证sinx+siny=2sin(x+y)/2*cos(x-y)/2 求证:sinx+siny=2sin(x+y)/2cos(x-y)/2 求证|sinx-siny|=|2sin[(x-y)/2]cos[(x+y)/2]| 1-2sinx cosx /COS^2X-SIN^2X =1-tanx/1+tanx 求证 求证 sinx(cos^2 2x-sin^2 2x) + 2cosx cos2x sin2x= sin 5x 提问数学难题求证：sin^2x*tanx+cos^2x/tanx+2sinx*cosx=tanx+1/tanx 为什么2sin(x/2)cos(x/2)=sinx sin(2x+y)/sinx-2cos(x+y) 化简 求化简(sinx+tanx)/cos^2x+sin^2x+cosx sinx*( cos x)^3/(1+sin^2x)的不定积分 sinx+cosx/sinx-cosx=2 求sinx/cos^3x +cosx/sin^3x sin（x+△x）-sinx 为啥等于2sin（△x/2）cos［x+（△x/2）］求证.. （1）已知：(4sinx-2cosx)/(5cosx+3sinx)=6/11 求sinx乘以cosx的值（2）证明(cosx/1+sinx) - (sinx/1+cosx)=2（cosx-sinx)/1+sinx+cosx(3)求证:sin²x乘以tanx + cos²x乘以cotx+2sinx乘以cosx=tanx+cotx要用 sin²X+cos²X=1 已知sinαcosβ=cos^βsinx/2cosx+sin^2αcosx/2sinx,求证:tgx=sinα/cosβ