Hello people! I have bought ''Calculus Made easy'' by Silvanus P. Thompson, I'm starting to teach myself calculus before actually taking the course. The problem discussed here will be about applying the power rule. Also, I'm not quite familiar with the use of LaTeX, so I'll try to make it as clear as possible without it. 1. The problem statement, all variables and given/known data Differentiate the following : y=³√[x^(-5)] 2. Relevant equations Just used the power rule really. 3. The attempt at a solution y = x^(-5/3) dy/dx = (-5/3)x^[(-5/3)-1] dy/dx = (-5/3)x^(-8/3) and I believe I'm finished here. But the textbook gives a different answer : dy/dx = (-5/3)x^(-8/5) And I really don't see how they got (-8/5) as a power of x. thanks for your time.