How do you evaluate csc1(2)?

1 Answer
Jun 24, 2016

π4

Explanation:

Let θ=csc1(2).

Since csc(x) and csc1(x) are inverse functions, this means that csc(θ)=2.

Another way of reaching that fact is to take the cosecant of both sides: csc(θ)=csc(csc1(2)), and since csc(csc1(x))=x, this becomes csc(θ)=2.

Taking the reciprocal of both sides, the equation becomes sin(θ)=12=22.

So, we want to find θ, or the angle where the value of sine is 22.

This is a well known value of sine. It occurs when θ=π4, which means that csc1(2)=π4.