A spherical balloon's radius increases at . How fast is its volume increasing when the radius is ? ()
Answer and explanation
Correct answer: C.
- Step 1: at .
- Step 2: Chain rule: .
Answer
.
Why not the others: : forgets to multiply by . : halves the correct answer. : is half the volume of the sphere at , not a rate of change.
Practise more Differentiation.
Free questions with an explanation for every one, and full timed ESAT (Engineering and Science Admissions Test) mock tests.