Given, ∫√x2−a2dx
=√x2−a2(x)−∫2x2√x2−a2xdx
=√x2−a2(x)−∫x2√x2−a2dx
=√x2−a2(x)−∫x2−a2+a2√x2−a2dx
=√x2−a2(x)−∫x2−a2√x2−a2dx+a2∫1√x2−a2dx
=√x2−a2(x)−∫√x2−a2dx+a2∫1√x2−a2dx
2∫√x2−a2dx=√x2−a2(x)+a2∫1√x2−a2dx
∫√x2−a2dx=12√x2−a2(x)+12a2log|x+√x2−a2|+c ....where c is constant term.