can u help me by solving this integral
Use integration by substitution:
Let $\displaystyle u(x) = \sin(x) +\cos(x)$. Then $\displaystyle \frac{du}{dx} = \cos(x)-\sin(x)~\implies~du = (-\sin(x) + \cos(x))dx$
Your integral becomes
$\displaystyle \int \left(\frac1{\sqrt{u}}\right) du$
Can you take it from here?