Question

How are these concepts of direct, inverse, and joint variation used in everyday life? Provide examples for each.

Answer 1

direct: \[y \alpha x \rightarrow y = kx\]=\]

Answer 2

inverse: \[y \alpha \frac{ 1 }{ x }\rightarrow y = \frac{ k }{ x }\]

Answer 3

y varies jointly as x and a constant

Answer 4

jointly: \[y = mx + c\]

Answer 5

The first is y varies directly as x
The second is y varies inversely as x
The third is y varies jointly as x and a constant where k is the proportionality constant