Question

Solve the optimization problem. HINT [See Example 2.]

Minimize S = x + y with xy = 4 and both x and y > 0.
S = ?

Answer 1

S = 4

Explanation:

X and Y are both factors of 4.

The factors of 4 are 1, 2, 4.

Evaluating all of the possibilities, we get:

x: 1, y:4 => S:5

x: 2, y:2 => S:4

x: 4, y:1 => S:5

Therefore, the lowest value of S is 4.