What is the composition of a function with its inverse? You should always have In the case of the function is only an inverse on the interval so you need to make sure that the value falls in this range (if it does not, find an angle in the range that has an equal cosine).

The secant is just the reciprocal of the cosine. Look at your unit circle: what common value of givesproblem 2: inverse sec(root 2)

for problem 2 I can't understand how to find out what the proper values are

Maybe this will make it more obvious:

Keep in mind that the range of is defined as (usually, but your textbook or instructor may have defined it another way).

Let Then the inverse, if it exists, satisfiesproblem 3 - find inverse of sin(x+2) -1

once again, boggled by how to do so