Parameterize the cylinder (call it
) by

with
and
. Then

Take the normal vector to
to be

Then the flux of
across
is


<span> D) Train A by a factor of 1.1
</span>Train A: <span>17/35</span><span> = 34.6</span>
<span>Train B: </span>Rate<span> is the </span>slope<span> of the </span>equation, 31.35
Thus,<span>34.6/31.35</span><span> = 1.1036</span>
Triangle ABC because the other ones are different from each other and there is only one of them.
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.