已知f(x)=3x+2,g(x)=x^2-1,求f(x+1),f[f(x0],f[g(x)],g[f(x)]
问题描述:
已知f(x)=3x+2,g(x)=x^2-1,求f(x+1),f[f(x0],f[g(x)],g[f(x)]
答
f(x)=3x+2
f(x+1)=3(x+1)+2=3x+5
f[f(x)]=f(3x+2)=3*(3x+2)+2=9x+8
f[g(x)]=f(x^2-1)=3*(x^2-1)+2=3x^2-1
g[f(x)]=g(3x+2)=(3x+2)^2-1=9x^2+12x+3