Differentiate $1/x^{1/2}$

Question

Differentiate $\dfrac{1}{x^{1/2}}.$

Is the answer $-x^{-3/2}/2$ ?

I was given this problem by a math teacher to solve in my head. I should be able to solve it but I want to check with you once and for all.

Answer 1

note that $$\frac{1}{x^{1/2}}=x^{-1/2}$$ so $$(x^{-1/2})'=-\frac{1}{2}x^{-3/2}$$