Equation of tangent at (2,3) to (y−2)2=x−1 is S1=0⇒x−2y+4=0 Required Area = Area of △OCB+ Area of OAPD - Area of △PCD =21(4×2)+∫03(y2−4y+5)dy−21(1×2)=4+[3y3−2y2+5y]03−1=4−9−18+15−1=28−19=9 sq. units 
(or) Area =∫03(2y−4−y2+4y−5)dy=∫03(−y2+6y−5)dy=−∫03(3−y)2dy=[3(y−3)3]03=327=9 sq.units