Originally Posted by

**Len** Name the curve with the given polar equation

1) $\displaystyle r=4$

$\displaystyle r^2=4^2

x^2+y^2=4^2$

Circle with radius 4 and origin (0,0)

2)$\displaystyle \Theta=\dfrac{2\Pi}{3}$

Stumped.

3)$\displaystyle r=-4\cos\Theta$

$\displaystyle \cos\Theta=\dfrac{x}{r}$

$\displaystyle => r=-4\dfrac{x}{r}$

$\displaystyle => r^2=-4x$

$\displaystyle x^2+4x+y^2=0$

$\displaystyle (x+2)^2+y^2=2^2$

Circle with radius 2 and origin (-2,0)

If someone could verify 1 & 3 and help with the 2 I would be most appreciative. Thanks.