Question

用换元法求f(2x+1)=（x的平方）+1,求f(x)

Answer 1

令t=2x+1,则x=(t-1)/2

f(t)=x^2+1=[(t-1)/2]^2+1=(t-1)^2/4+1=t^/4-t/2+5/4

所以f(x)=x^2/4-x/2+5/4