P 2 = 1。
That is, x 2+y 2 = 1
Then the point set of p= 1 forms a circle with (0,0) as the center and 1 as the radius.
Because θ = 45.
Therefore, x = PCOS θ = PSIN θ = Y.
That is to say, the horizontal and vertical coordinates of the point (x, y) are equal.
Therefore, the point set θ=π/4 is the straight line y=x in the plane rectangular coordinate system.