Know your limits! (III)

Calculus Level 2

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