The rate of change (in cm2/s) of the total surface area of a hemisphere with respect to radius r at $r=\sqrt[3]{1.331}$ cm is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → $6.6 \pi$
TSA of hemisphere
$T=3πr^2$
let $\frac{dr}{dt}=1$
$\frac{dT}{dr}=6πr\frac{dr}{dt}$
$=6π×\sqrt[3]{1.331}$
$=6π×1.1$
$=6.6π$ sq. units