# Math Help - Rectangular into polar form

1. ## Rectangular into polar form

How about x^2 + 2xy + y^2 =9

Can someone show me this step by step?

Thank you so much,
Caleb

2. Originally Posted by cmr7
How about x^2 + 2xy + y^2 =9

Can someone show me this step by step?

Thank you so much,
Caleb
Substitute $x = r \cos \theta$ and $y = r \sin \theta$ and simplify. Note that $x^2 + y^2 = r^2$.

3. Thank You Mr. Fantastic!!