f(x)=x|x|+2x (x

f(X)=f(X+2)(x f(x)=x/(x^2+1) 函数f(x)=x-2 (x f(x)=x^2x 求导 f(x)=｛x^2+x(x≤0),-x^2+x(x＞0) x-2 ,X>=0 f(x)=f[f(x+5)],x分段函数f(x)= x-2 ,X>=0 f[f(x+5)],x 已知函数f(x)=x^2+2x+a,g(x)=f(x)/x. 已知函数f（x)=2x+1,x>=0;f(x)=|x|,x f(x)=x(x-1)(x-2)(x-3)(x-4) f'(1)=? f(x)为奇函数,x>0,f(x)=sin 2x+cos x,则x f(x-1)=x^2-2x+3(x f(x)=min{x^2-2,x,4-x}