Find the polar coordinates of this point with the given rectangular coordinates. Use 0 < or = theta < 2pi and r > or + to 0.
I understand how to get r but how do i get theta expressed in pi?
Draw a diagram. Construct a right angled triangle in the third quadrant (where (-2, -5) is.
Use trigonometry (tan^-1) to find the acute angle below the neg x-axis ( this must be in radians). Add this angle to pi (to get the total angle anticlockwise from the pos x-axis). Then you'll have theta.
Note: If the point was (-2, +5), you'd find the same angle (this time in the second quadrant) and subtract it from pi.
A diagram makes everything clear.