# Variation

• Dec 4th 2008, 01:36 PM
magentarita
Variation
Express the following statement as a formula:

w varies jointly with square root of y and z squared and inversely as x cubed.
• Dec 4th 2008, 04:14 PM
nzmathman
This means that $\displaystyle w$ is a function directly proportional to $\displaystyle \sqrt{y}$, $\displaystyle z^2$ and $\displaystyle \frac{1}{x^3}$

$\displaystyle w = k \times \frac{z^2 \, \sqrt{y}}{x^3}$

where k is a constant.

Or I may be wrong? If w varies jointly it could be $\displaystyle w = k \times \frac{z^2 \pm \sqrt{y}}{x^3}$
• Dec 5th 2008, 06:45 AM
magentarita
ok...
Quote:

Originally Posted by nzmathman
This means that $\displaystyle w$ is a function directly proportional to $\displaystyle \sqrt{y}$, $\displaystyle z^2$ and $\displaystyle \frac{1}{x^3}$

$\displaystyle w = k \times \frac{z^2 \, \sqrt{y}}{x^3}$

where k is a constant.

Or I may be wrong? If w varies jointly it could be $\displaystyle w = k \times \frac{z^2 \pm \sqrt{y}}{x^3}$

Well-done!