sin(x/2+50)=30

sin(x/2+50)=30 证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4 傅里叶级数作图f（x）=2sin[x] - sin[2x] + 2/3sin[3x] - 1/2sin[4x]我用mathematica输入程序Plot[{2sin[x],-2sin[x],2sin[x] - sin[2x],-2sin[x] + sin[2x],2sin[x] - sin[2x] + 2/3sin[3x],-2sin[x] + sin[2x] - 2/3sin[3x],2sin[x] - sin[2x] + 2/3si 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 已知sin(30-x)=1/4,则sin(30+2x)=? 已知sin(30-x)=1/4,则sin(30+2x)=? 已知sin(x+30°）=2sin(x-30°）,则tanx=( ) y=[sin^2(x)]*[sin^2(x)]求导 2sin(x+π/4)sin(x-π/4)=? ∫sin(6x)sin(2x)dx=? 解方程 sin 2x + sin x = 0 sin(x-30)cos30=? Sin2x=sin^2x 高一三角函数化简 sin^2(x-30)+sin^2(x+30)-sin^2(x) 一道三角恒等式证明题请证明sin(x+y)sin(x-y)=sin^2(x)-sin^2(y) s = 2*sin(x)-sin(2*x)+2/3*sin(3*x)-1/2*sin(4*x)+2/5*sin(5*x)用matlab画图,求教啊 证明一个sin&cos的等式证明 1+sin^2(x)+sin^4(x)+sin^6(x)=[1-sin^8(x)]/[cos^2(x)] 已知sin(x)+3cos(x)=2,求sin(x)-cos(x)/sin(x)+cos(x)=?