Practice Optimization in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The process of using derivatives to systematically find maximum or minimum values of a function over a domain.

Find where the function hits its peaks (maxima) and valleys (minima) by finding where the slope is zero.

Showing a random 20 of 50 problems.

Example 1

easy
Find the absolute minimum of f(x)=(x−3)2+1.

Example 2

hard
Find the dimensions of the right circular cone of maximum volume that can be inscribed in a sphere of radius R.

Example 3

medium
Find two non-negative numbers whose sum is 20 and whose product is maximum.

Example 4

hard
Find the absolute minimum value of f(x)=x2+16x for x>0.

Example 5

medium
Find the dimensions of a rectangle with perimeter 20 that maximizes area.

Example 6

easy
Where does f(x)=x2 attain its minimum?

Example 7

medium
Find the absolute maximum and minimum of f(x)=x3−6x2+9x+1 on [0,4].

Example 8

medium
Find the absolute extrema of f(x)=sin⁡x+cos⁡x on [0,2π].

Example 9

hard
A right triangle with the right angle at the origin has legs along the positive axes. The hypotenuse passes through (3,4). Find the minimum area of the triangle.

Example 10

easy
Find the critical points of f(x)=x3−3x.

Example 11

easy
Find the absolute max of f(x)=4−x2 on [−1,1].

Example 12

medium
A poster has area 180 cm2. If margins are 3 cm on top and bottom and 2 cm on each side, what poster dimensions maximize the printed area?

Example 13

medium
A page must contain 50 in2 of printed text, with margins of 1 in on top/bottom and 2 in on each side. What page dimensions minimize total page area?

Example 14

easy
What does the second derivative test tell you if f′(c)=0 and f′′(c)>0?

Example 15

challenge
Snell's law: a swimmer at (0,4) on land swims to point (x,0) on a straight shoreline, then swims in the water to (10,−3). Land speed 5 m/s, water speed 3 m/s. Set up the time function T(x) and write the equation that x must satisfy (don't solve numerically).

Example 16

medium
A box with a square base and open top has volume 32. Minimize surface area.

Example 17

medium
Classify the critical point of f(x)=−x2+6x using the second derivative test.

Example 18

challenge
A 12 cm wire is cut into two pieces, one bent into a square and one into a circle. Where to cut to minimize total area? (Set up the critical-point equation.)

Example 19

easy
Is x=0 a max, min, or neither for f(x)=x3?

Example 20

challenge
Maximize the area of a rectangle inscribed under y=4−x2 (above the x-axis), with base on the axis.