Find f if f′(x)=4/sqrt(1−x^2) and f(12)=5.

Answer 1

since d/dx arcsin(x) = 1/√(1-x^2) you get

4arcsin(x) + C
Unfortunately, arcsin(12) is undefined. Maybe you are one of those people who cannot figure out how to type fractions.
4arcsin(1/2) + C = 5
4 * π/6 + C = 5
now finish it off