Evaluate

in these type of problems we put the value of x=a tank

That is mean that dx=a sec²k dk

= ∫ a. sec k. a. sec²k dk

=∫ a² sec³k dk

By upper solve questions we can find out the value of integration of sec³x,whixh is equal to

Put the value of integration of sec³x in above equation we get our finally integral which is –

Now put the value of k which is tan^-1(x/a) in above equation-