Question

数学题求助f(g(x)) = g(f(x))

Answer 1

f(g(0))=f(c)=g(f(0))=a*(f(0))²+b*f(0)+c

即f(c)=a*(f(0))²+b*f(0)+c

c是任意常数 令c=0

f（0）=a*(f(0))²+b*f(0)+f(0)

a,b也是任意常数 故f(0)=0

f(x)=x