To convert this rectangular coordinate (x,y)(x,y) to a polar coordinate (r, theta)(r,θ), use the following formulas:
r^2=x^2+y^2r2=x2+y2
tan theta=y/xtanθ=yx
r^2=(-200)^2+(10)^2r2=(−200)2+(10)2
r^2=40100r2=40100
r=sqrt40100r=√40100
r=10sqrt401r=10√401
tan theta=y/xtanθ=yx
tan theta=10/-200tanθ=10−200
theta=tan^-1(10/-200)θ=tan−1(10−200)
theta~~-0.05θ≈−0.05
The angle -0.05−0.05 radians is in Quadrant IVIV, while the coordinate (-200, 10)(−200,10) is in Quadrant IIII. The angle is wrong because we used the arctanarctan function, which only has a range of [-pi/2, pi/2][−π2,π2]. To find the correct angle, add piπ to thetaθ.
-0.05 + pi = 3.09−0.05+π=3.09
So, the polar coordinate is (10sqrt401, 3.09)(10√401,3.09) or (200.25, 3.09)(200.25,3.09).