f(x)=(x+1)^3 (x-1)^3 prove if its increasing or decreasing using geometrical representation

Dear Student

(x-1)³(x+1)³= (x²-1)³
on differentiation
f’= 3(x²-1)².(2x) = +ve for +ve value of x and negative for negative value of x

Hence,it is neither increasing nor decreasing

Thanks