Let be a function such that
for all .
Let be a function such that for all .
Then the number of points at which has a local maximum is:
Let be a function such that
for all .
Let be a function such that for all .
Then the number of points at which has a local maximum is:
Solution
✅ Correct Option: 2
Given , we need to find local maxima of .
Since , differentiating:
For critical points, when , giving us .
To determine which critical points are local maxima, we analyze the sign of in each interval.
The factor is always non-negative, so the sign depends on :
| Interval | sign | behavior | ||
|---|---|---|---|---|
| Increasing | ||||
| Decreasing | ||||
| Increasing |
From the behavior of :
- At : changes from increasing to decreasing → local maximum
- At : changes from decreasing to increasing → local minimum
- At : keeps increasing (no sign change) → no extremum
Since is a monotonically increasing transformation of (for ), inherits the same extremum behavior as .
Therefore, has a local maximum only at .
The answer is 1.