Convert between (r, θ) and (x, y) with a vector diagram.
Input
Answer
Steps
Why it works
Polar and rectangular coordinates describe the same point: x = r cosθ, y = r sinθ projects the radius onto the axes; going back, r = √(x²+y²) and θ = atan2(y, x), which picks the correct quadrant automatically — plain arctan(y/x) cannot.
