Given that f(x)=x1 and (gf)(x)=3x2+2, find the function of g in similar form? Thank you

1 Answer
Aug 11, 2018

One possibility is g(x)=3x2+6x+5

Explanation:

There are infinite g's which satisfy this condition. Let us consider as g pertaining to the polynomials, for instance let

g(x)=ax2+bx+c

then

g(f(x))=a(f(x))2+bf(x)+c=a(x1)2+b(x1)+c

so

g(f(x))=(a3)x2+(b2a)x+a+cb+2=3x2+2

and now comparing coeficients

a=3,b=6,c=5

hence g(x)=3x2+6x+5