Question

Identify the variation as direct, inverse, joint or combined.
xy = c

Answer 1

Joint variation.

Explanation:

A joint variation is where a variable depends on two other variables, that is, it can change because of two other variables, and it's a direct relation, if both variables increase the dependent variable also increase, and vice versa.

In this case, we see that c depends on x and y, if any of those two variables increase, c will also increase.

Therefore, this is joint variation.

Answer 2

This is a joint variation. In essence, c varies jointly as x and y