Mathematics

Mathematics

Problem

A firm’s profit (in thousand rupees) from producing and selling xx hundred units of a product is modelled by P(x)=−x4+4x3+15,P(x)=-x^{4}+4x^{3}+15, where 0≤x≤50\le x\le 5. Analyse this model as follows. a. (i) Find P′(x)P'(x) and determine all stationary points of PP in the given interval. b. (ii) Compute P′′(x)P''(x) and apply it to classify each stationary point, mentioning any point where P′′(x)=0P''(x)=0. c. (iii) For every point where the conclusion in part (ii) is inconclusive, investigate the sign of P′(x)P'(x) on appropriate intervals to decide its nature. d. (iv) Using all the information above and the values of PP at the endpoints, find the production level that gives the maximum profit and state the corresponding maximum profit.
Intuitive explanation

This problem asks you to understand profit as a function and find where it reaches its peak—a classic optimization task. The key insight is that maximum profit occurs where the derivative equals zero, so you'll take P′(x)P'(x), solve for critical points, and then check which one (and the endpoints) actually gives the largest value. Think of the derivative as the rate of change of profit: when it's positive, profit is climbing; when it's zero, you've hit a local peak or valley.

Intuitive explanation

This problem asks you to understand profit as a function and find where it reaches its peak—a classic optimization task. The key insight is that maximum profit occurs where the derivative equals zero, so you'll take P′(x)P'(x), solve for critical points, and then check which one (and the endpoints) actually gives the largest value. Think of the derivative as the rate of change of profit: when it's positive, profit is climbing; when it's zero, you've hit a local peak or valley.

Browse the problem library