Oi
Just calculating the differential. Step by step:

If you want to know where the tangent has no slope:
Try this solution:
if given dr/dt=8e^t -e^(2t), then
One tick behind one is 3/4, 1/8 is basically half of 1/4, so find 1/4 and find 1/8, 0 is sort of obvious but then not obvious. three ticks behind 3/4. 2 2/3, count UP from 1 1/4 to find 2 2/3. I really hope I helped! :)
Answer:
Step-by-step explanation:
Remark
The angle formed by the intersection of a tangent to a circle and an intersecting secant is 1/2 (Arc PS - arc PR)
PS = 208
PR = 74
Solution
x = 1/2 (208 - 74)
x = 1/2 (134)
x = 67
2nd answer.
any pts in the shaded region satisfies your simultaneous equation.