sinx cosx dx/ [a2cos2x + b2sin2x]
=> sin2x dx/2 [a2cos2x + b2sin2x] .............(A)
Let [a2cos2x + b2sin2x] = t
Differentiating both the sides, we have
sin 2x [b2-a2] dx = dt
=> sin 2x dx = dt / [b2-a2]
Substituting in equation (A)
integral of dt /{2t [b2-a2] }
=> ln (t) / {2 [b2-a2]}
substitute the value of 't' and get the answer :)