# New interest in Physics.

1. Mar 27, 2008

### matthewmystar

Hey everyone,

I have recently developed a strong interest in physics. To the point where I am changing my major from computer science to computational physics. Anyway, I am having a problem understanding a formula in a book I have on relativity. The problem is:
90$$\circ$$ = arcsec(300/1000). Now I know some Trig. but I haven't done it in awhile and don't remember arcsec at all. Can anyone explain to me why that problem equals 90 degrees.

Thanks,
Daniel

2. Mar 27, 2008

### Math Jeans

secx is equal to 1/cosx. arcsecx would then be equal to the angle that causes sec to equal x.

However, because cosx is always <= 1, then 1/cosx cannot be less than 1. Therefore, if 300/1000=3/10, arcsec(300/1000) shouldn't exist.

3. Mar 27, 2008

### matthewmystar

That is was the conclusion I was coming up with also. Maybe I am misunderstanding the problem.
This is the exact problem from the book:http://books.google.com/books?id=fz...q9xmXR&sig=ZM6PZ9v6XRaqWad6pn9UxlufThQ&hl=en"

Last edited by a moderator: Apr 23, 2017
4. Mar 27, 2008

### bassplayer142

5. Mar 27, 2008

### dst

6. Mar 28, 2008

### Phlogistonian

The formula should say arccotangent, not arcsecant.