Find The Points Beyond A Line Using Python

With reference to the question asked here Drawing a line given the angle and a point on the line, I have written a python function 'find_normal' which returns the slope and y-inter

Solution 1:

If c and s are the angle's cosine and sine, the function must return True for a point (x, y) iff c*(x-x1) + s*(y-y1) >= 0 where (x1,y1) is any point on the red line.