Question

y = e^(-2x)(tanx -1 )^2
Find the minimum of value of dy/dx without differentiating

Answer 1

Well, to cut down on confusion, \(\tfrac{dy}{dx}\) is at a minimum when \(\tfrac{d^2y}{dx^2}=0\) so try to imagine where the concavity of y is zero.

Answer 2

Oh sorry the question is find the value of x when dy/dx is least?