Question

Pre-Calculus Help? Polar and Parametric Equations?

Answer 1

$\bf x=rcos(\theta )\implies \cfrac{x}{cos(\theta )}=r\\\\ y=rsin(\theta )\implies \cfrac{y}{sin(\theta )}=r \\\\ -------------------------------\\\\ r=3cos(\theta )\implies \cfrac{x}{cos(\theta )}=3cos(\theta )\implies x=3cos(\theta )cos(\theta ) \\\\\\ \boxed{x=3cos^2(\theta )} \\\\\\ r=3cos(\theta )\implies \cfrac{y}{sin(\theta )}=3cos(\theta )\implies \boxed{y=3cos(\theta )sin(\theta )}$