Question

Write three functions.

In the first function, y should vary directly with x.
In the second function, y should vary inversely with x.
In the third function, the relationship between x and y should be neither inverse variation nor direct variation.

Describe the graph of each function and give a real-world example for each.

Answer 1

1) y = kx . . . . . for some constant k
.. The volume of an ideal gas is directly proportional to its absolute temperature.

2) y = k/x . . . . for some constant k
.. The volume of an ideal gas is inversely proportional to its pressure.

3) y = 1.8x +32
.. Temperatures in degrees Fahrenheit are linearly related to those in degrees Celsius, but the relation is neither directly nor inversely proprotional.