Question

If the polar coordinates of the point ( x , y ) are ( r , θ ), determine the polar coordinates for the following points. (Use any variable or symbol stated above as necessary.)

a) -x,y
b)-2x,-2y
c)3x,-3y

I don't understand what they are asking for because i tried the r=sqrt(x^2+y^2) and that theta = tan^-1(y/x) and it was wrong.

Answer 1

Now, what are r' and θ' for the point (-x,y) ?

Answer 2

it is r and theta

Answer 3

now I am only having trouble finding the theta for the last two points.

Answer 4

No, polar coordinates for the first point are (refer to drawing):

\(r_1=r\)
\(\theta_1=\pi-\theta\)