Question

How do you convert `x^2 + y^2 = 9` into polar form?

Answer 1

I found: `r=3`

Explanation:

Consider the following diagram:

We can see that the relationships between rectangular and polar coordinates are:
`r=sqrt(x^2+y^2)`
`theta=arctan(y/x)`
and:
`x=rcos(theta)`
`y=rsin(theta)`

Given our equation we can take the square root of both sides:
`sqrt(x^2+y^2)=sqrt(9)`
Using our relationship:
`r=3`