# Thread: need graph for polar eqn r = 6 - 4 sin theta

1. ## need graph for polar eqn r = 6 - 4 sin theta

Howwould I attempt to begin the polar eqn : ( I need to graph too)

r = 6 - 4 sin theta

2. Start with known values and plot them.

theta = 0
sin(0) = 0
6 - 4sin(0) = 6

What other exact values of the sine function do you know?

3. ## Re: trig...polar equation

Hello, Chevy_meg!

How would I graph: $\:r \:=\: 6\,-\,4\sin\theta$

You're expected to recognize the curve . . . a "limacon".
. . In this one, the cusp does not "go into the origin".

As tkhunny suggested, plot some points.

. . $\begin{array}{ccccccccc}\hline \;\theta & | & 0 & | & \frac{\pi}{2} & | & \pi & | & \frac{3\pi}{2}\; \\ \hline \;r & | & 6 & | & 2 & | & 6 & | & 10\; \\ \hline \end{array}$

This gives us the orientation of the limacon.
Code:
               *    |    *
*     * | *     *
*         o2        *
*          |          *
|
- - o - - - - - + - - - - - o - -
6*           |           *6
*           |           *
|
*          |          *
*         |         *
*       |       *
*    |    *
* o *
|10

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