Find the derivative of the functions given by `f(x)= (1+x)(1+x^(2))(1+x^(4))(1+x^(8))` and hence find f'(1).

Answer

`(1+x)(1+x^2)(1+x^4)(1+x^8)[(1)/(1+x)+(2x)/(1+x^2)+(4x^3)/(1+x^4)+(8x^7)/(1+x^8)]; f'(1)=120`