请问f(x)=[1/(sinα)^2]+[1/(cosα)^2]的值域怎么求?

请问f(x)=[1/(sinα)^2]+[1/(cosα)^2]的值域怎么求? f(sin 2/x )=1+cosx 求f(x) 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f(sin-1)=cos2x+2,求f(x) 若f(x)=sin πx/6,则f(1)+f(2)+...+f(102)=? 若f(x)=sin(π/4)x,求f(1)+f(2)+.+f(2010) 已知函数f(x)=(1+1 anx)sin^2x+m sin(x+π/4)sin(x-π/4) f(x)=（1+cotx)sin^2x-2sin(x+π/4)sin(x-π/4)还有一题, 函数F(X)=2sin(x/2)sin(α-X/2）的最大值为? f(x)=(1+1/tanx)sin(x)^2化简 f(x)=sin^2x+sinxcosx-1/2,化简 已知函数f(x)=-1/2+sin(5/2x)/2sin(x/2)(0 化简f(x)=(1+cos2x)sin^2x f(x)=sin(πx^2)(-1 已知f(x)=sin(πx/2+α),且f(2009)=1,则f(2010)= F(X)=SIN(πx/2+α),且f(2010=1)则f(2012=?) 若f(x)=sinπ/2x,则f(1)+f(2)+f(3)+...+f(2012)+f(2013)= f(x)=sin（nπ/3）,f(1)+f(2)+...+f(2010)等于