y=sin(2X)-8(sinX+cosX)+19(0小于等于X小于等于π) 求Ymax Ymin

证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx 求证sin（2x+y)/sinx-2cos(x+y)=siny/sinx 求证：sin(2x+y)/sinx-2cos(x+y)=siny/sinx sin(2x+y)/sinx-2cos(x+y) 化简 曲线Y= sin x 1_________ - __ 求导?sin x +cos x 2sinx /(sinx +cosx ) - 1/2 已知sinθ+cosθ=2sinx,sinθcosθ=sin²y,求证：4cos²2x=cos²2y y= sin x cos x+sinx+cosx的值域 请问怎么证明sinX+sin(X+Y)+sin(X+2Y)/cosX+cos(X+Y)+cos(X+2Y)=tan(X+Y), 请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2) 为什么sin（x+y) - sinx = 2cos(x+y/2)siny/2 求推导sinx-siny=2cos（(x+y)/2)sin((x-y)/2) 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]| sin(x+y)-sinx=2siny/2·cos(x+y/2)怎么来的 已知sinx=3/5,x∈(π/2,π),求【sin(x+y)+sin(x-y)】/【cos（x+y）+cos（x-y）】的值 y=sin^2 x+3sinx-1 2.y=-cos^2 x+sinx+3,求下列函数值域 y=1+sin^2x和y=cos（sinx）为什么是偶函数