# How do you determine a point in common of #r = 1 + cos theta# and #r = 2 cos theta#?

##### 1 Answer

(2, 0) and r = 0.

#### Explanation:

The two meet when

Therein,

The first equation

for

The second

at (1,0) and the whole circle is drawn for

Interestingly, seemingly common point r=0 is not revealed here.

The reason is that,,

for

and for

Thus the polar coordinate

This disambiguation is important to include, as we see, r = 0 as a

common point that is reached in different directions.

This is a reason for my calling r = 0 a null vector that has contextual

direction.