Christmas MT's answer to Geraldine's Secondary 4 A Maths question.
e^(-2) is simply to put e into the denominator;
e^(1/2) is simply the square root.
Moreover, the two e's are summed together, not minused, so there is no way it can ever give 0.
Furthermore, there is no x value where you can make 2e^x or e^(-2x) equals to zero. Remember, e^0 = 1.
So, f'(x) is always > 0, meaning it can never be 0 :)