Which one question? there is multiple in there.
Answer:
pi/6
Step-by-step explanation:
An inverse sin is asking which point on the unit circle has that value as its sin
Which in this case, is pi/6

Hope this helps
Answer:

Step-by-step explanation:
We know (Ohm second law) that
where k inlcudes the rest of the parameters (material, lenght). In our situation we have k=
. The moment the diameter becomes 8mm R becomes

Solve the "f" function with substitute 4 and solve the "g" function with what we get for the "f" function.
f(4) = 2(8) + 3
f(4) = 16 + 3
f(4) = 19
g(19) = 4(19) - 1
g(19) = 76 - 1
g(19) = 75
Best of Luck!