Find the value(s) of x for which y=[x(x-2)]^2 is an increasing function.
Solution:
f(x)=[x(x-2)]^2 We know for increasing function we have f'(x)≥0 Therefore, f'(x)=2[x(x-2)][d/dx(x-2)] or, f'(x)=2[x(x-2)][d/dx(x^2-2x)]=2x(x-2)(2x-2) =4x(x-2)(x-1) For f'(x)≥0, i.e., 4x(x-1)(x-2)≥0 The values of x are: x∈[0,1]∪[2,∞).