At what point does the cubic function attain its local minimum?
Answer and explanation
Correct answer: B.
At : , which is a local maximum.
At : , which is a local minimum. Thus, the local minimum occurs at .
At : , which is a local minimum. Thus, the local minimum occurs at .
- Step 1: Find the first derivative: .
- Step 2: Setting gives stationary points at and .
- Step 3: Find the second derivative: .
Answer
.
Why not the others: is the local maximum point; is the inflection point where ; is the -intercept.
Practise more Limits, continuity and differentiability.
Free questions with an explanation for every one, and full timed JEE Main mock tests.