## Calculus 8th Edition

$$r=\frac{2}{cos\theta + sin \theta}$$
As we are given that $x+y=2$ To convert this equation into polar equation, we will substitute $x=rcos\theta$ and $y=rsin \theta$ Thus, $$rcos\theta + rsin \theta =2$$ or $$r=\frac{2}{cos\theta + sin \theta}$$