I will be grateful for your help in deciphering the meaning of a paragraph from the book. I honestly don't understand how they got the semi-circle on the xy graph by transferring it from rθ graph.
I attach the screen shot from the book.
The Attempt at a Solution
(1) if on xy graph values of r are on the x-axis, and values of θ are on the y axis, then when r = 6, we have to plot θ = 0, it's clear and corresponds to the point (6,0);
(2) but then when r = 3√2, θ = π/4, and when r = 0, θ = π/2, so I don't understand how could they "finish" the curve at the origin, namely at (0,0)? How that xy curve was formed by transforming values from the rθ curve?
Thank you very much!