Given the point:
Use the equation:
r = sqrt(x^2 + y^2r=√x2+y2
r = sqrt((-3sqrt(3))^2 + (-3)^2)r=√(−3√3)2+(−3)2
r = sqrt(27 + 9)r=√27+9
r = 6r=6
There are many equations for the angle, thetaθ; which one you use depends on x and y:
"[1] "theta = tan^-1(y/x); x > 0 and y ge 0[1] θ=tan−1(yx);x>0andy≥0
"[2] "theta = pi/2; x = 0 and y > 0[2] θ=π2;x=0andy>0
"[3] " theta = pi + tan^-1(y/x); x < 0[3] θ=π+tan−1(yx);x<0
"[4] "theta = (3pi)/2; x = 0 and y < 0[4] θ=3π2;x=0andy<0
"[5] "theta = 2pi + tan^-1(y/x); x > 0 and y < 0[5] θ=2π+tan−1(yx);x>0andy<0
Because x = -3sqrt(3)x=−3√3, then we do not care about the value of y and we use equation [3}:
theta = pi + tan^-1((-3)/(-3sqrt(3))); x < 0θ=π+tan−1(−3−3√3);x<0
theta = (7pi)/6θ=7π6