Chapter 11.6, Problem 39PPE

To determine

To prove that the formula of time represent a direct variation or an inverse variation. $C=2\pi r$

Answer to Problem 39PPE

The reason is given in last of explanation

Explanation of Solution

Given:

Given

  $C=2\pi r$

Calculation:

In order to solve the question firstly we show the circumference of circle given in question

  $\begin{array}{l}C=2\pi r\\ Cisy,risx,kis2\pi r\end{array}$

As given calculation in above is that circumference of circle C represents $y$ , and radius $r$ represents $x$ and constant of variation $k$ is $2\pi$

So from the concept of direct variation $y=kx$

So as form the above expression it is direct variation

Hence proved

Thus, the solution is correct.