You multiply by -5 to find any next term. so next two are 500 then -2500
A straight angle is equal to 180 degrees. 180-80=100. 100-60=40. so y=40. vertical angles are congruent so x=40 degrees.
X(u, v) = (2(v - c) / (d - c) + 1)cos(pi * (u - a) / (2b - 2a))
y(u, v) = (2(v - c) / (d - c) + 1)sin(pi * (u - a) / (2b - 2a))
As
v ranges from c to d, 2(v - c) / (d - c) + 1 will range from 1 to 3,
which is the perfect range for the radius. As u ranges from a to b, pi *
(u - a) / (2b - 2a) will range from 0 to pi/2, which is the perfect
range for the angle. So, this maps the rectangle to R.
Where is the picture of the triangle?