Know your limits! (IV)

Calculus Level 3

Evaluate $\lim_{x\rightarrow1} \frac{x^{1/2}-(2-x)^{1/3}}{x^2+x-2} .$ If your answer can be expressed as $\dfrac{a}{b}$ where $a$ and $b$ are coprime positive integers, find the value of $a+b$ .