What are the polar coordinates of (−2, −9)?
1 Answer
May 4, 2017
Explanation:
"to convert from "color(blue)"cartesian to polar coordinates"
"that is " (x,y)to(r,theta)" where"
• r=sqrt(x^2+y^2)
• theta=tan^-1(y/x);-pi < theta <= pi
rArrr=sqrt((-2)^2+(-9)^2)=sqrt85
(-2,-9)" is in the third quadrant so must ensure that "
theta" is in the third quadrant"
theta=tan^-1(9/2)=1.35larr" related acute angle"
rArrtheta=-pi+1.35=-1.79larr" in third quadrant"
rArr(-2,-9)to(sqrt85,-1.79)
