# Homework Help: Inverse trig equation

1. Dec 14, 2009

### IniquiTrance

1. The problem statement, all variables and given/known data

I have knocked a problem down to:

$$-arcsec \frac{3x}{4}$$

but my textbook gives the answer as:

$$arctan \frac{4}{\sqrt{9x^2 - 16}}$$

Are these somehow equivalent?

Thanks

2. Relevant equations

3. The attempt at a solution

2. Dec 14, 2009

### Staff: Mentor

I don't think so. However, I get arccsc (3x/4) being equal to arctan(4/sqrt(9x^2 - 16))