IF F( X) IS A POLYNOMIAL FUNCTION SATISFYING F(X)*F(1/X)=F(X) + F(1/X),AND F(3)=28 ,THEN F(4) IS EQUAL TOA.63B.65C.68D.67 Share with your friends Share 6 Rajat Sethi answered this If f(x) ×f(1x)=f(x)+f(1x),thenf(x)=1±xnNow,f(3)=281+3n=28 or 1-3n=283n=27 or 3n=-27 ( not possible)∴n=3∴f(x)=1+x3f(4)=1+43=65 7 View Full Answer Niranjan.kamath answered this f(x)*f(1/x) = f(x) + f(1/x) is satisfied by the function f(x) = 1 + xk .Given: f(3) = 28 i.e 1 + 3k = 28 i.e 3k = 27 or k = 3. So, f(x) = 1 + x3 . Now, f(4) = 1 + 43 = 65 Option b). 3