Question

(1 point) Find the area of the surface obtained by rotating the curve y = yæ about y-axis for 1 < y < 2. Area:

Answer 1

प Yo ako L t=y=a Surface area ? Surface area of revolution is given as S fo ds Colegio dy csytd 21 x ds 3

y = x Taking cube both side y² = a 2 Surface area, s QT X +(dx dy (hp da dy d(y) che he S hip ho) + 1 f she 2 x 1+ T 2. sh Itay4 dy y regyh dy Put t tays Take derivative 9x4 y dy dt y'dy 36 y 3 fizayn dy JE 3 fande an 36 n+ > 36 t/2+1 th +312 36 (3/2) ut 54

sa 211 yo itayu dy - (1+994 3/2 54 y e L (1+x23/2 54 6149x29)}] ale] 3/2 ID T 27 (145/ 199.48 Ans! Area 199.48 2