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)#
