# How do you find the cartesian graph of r cos(θ) = 9?

Dec 7, 2015

$x = 9$

#### Explanation:

$\cos \left(\theta\right) = \frac{{x}_{\theta}}{\sqrt{{\left({x}_{\theta}\right)}^{2} + {\left({y}_{\theta}\right)}^{2}}}$

r= sqrt((x_theta)^2+(y_theta)^2))

Therefore
color(white)("XXX")rcos(theta) = cancel(sqrt((x_theta)^2+(y_theta)^2))xx (x_theta)/(cancel(sqrt((x_theta)^2+(y_theta)^2))

and since $r \cdot \cos \left(\theta\right) = 9$

$\textcolor{w h i t e}{\text{XXX}} {x}_{\theta} = 9$