A Joint probability density function is given by the following function:
c * y-2 x-3 if x > 1, y > 1, and x > y
f(x,y) = c * x-2 y-3 if x > 1, y > 1, and y > x
0 otherwise
Find an approximate value for the probability that a point (x, y) is within the triangle formed by the points (1,1), (5, 3), and (3, 5) by first finding the value c.
(please show a step-by-step solution)