A Frozen Variable

Problem

Let f(x)=aln⁡x+(x+1)2f(x) = a\ln x + (x+1)^2 with a≠0a \neq 0 and x>0x > 0.

1. Find the intervals on which f(x)f(x) is monotonic. 2. If

f(x)−x2a⩽0f(x) - \frac{x^2}{a} \leqslant 0

holds for every x∈[1,+∞)x \in [1, +\infty), find the range of possible values of aa.

Answer

Solution

Difficulty6/10
Topicscalculus, Monotonicity, Estimation, inequality, Casework

Whiteboard

Your sketch is saved only in this browser. To share it, export your drawing as an image (whiteboard menu → Export as → PNG), then upload that image in the comments below.

Discussion

Ask questions, share alternate solutions, and use LaTeX freely.

0 comments
Log in to join the discussion.

No comments yet.