∫0π2/4cosx dx
π-2
π+2
π2−1
2
Put x=t⇒x=t2⇒dx=2tdt∫0π2/4 cosxdx=∫0π/2 (cost)⋅2tdt LL⇒ t=0,U.Lt=π24⇒t=π2 = 2t sint π20 -∫0π22sint dt =π-2