# Pre-Calculus Homework help

• Nov 29th 2008, 10:58 AM
PrattX
Pre-Calculus Homework help
Ok here are the directions on the worksheet that I got from my Pre-Calculus teacher:
Find the exact value of each expression. If it is defined.

1. sin -1 1/2

P.S: I dont know how to type i sub script can someone help me with that?
• Nov 29th 2008, 11:22 AM
Shyam
Quote:

Originally Posted by PrattX
Ok here are the directions on the worksheet that I got from my Pre-Calculus teacher:
Find the exact value of each expression. If it is defined.

1. sin -1 1/2

P.S: I dont know how to type i sub script can someone help me with that?

$\sin^{-1} \left(\frac{1}{2}\right)$

$= 30^{\circ}$
• Nov 29th 2008, 11:25 AM
PrattX
How di you get that answer?
• Nov 29th 2008, 11:30 AM
skeeter
• Nov 29th 2008, 11:42 AM
PrattX
ok I'm starting to understand but I thought it would be 210 degrees becuase it's the inverse of sin. I'm still a little confused.
• Nov 29th 2008, 11:46 AM
skeeter
inverse sine is only defined in quadrants I and IV

range of the inverse sine function is

$-\frac{\pi}{2} \leq y \leq \frac{\pi}{2}$
• Nov 29th 2008, 11:50 AM
PrattX
oh ok..can you just name all the inverses of all the trigonometric funtions so I can write them down for a latter date.
• Nov 29th 2008, 12:00 PM
skeeter
research it yourself ...

inverse trig functions - Google Search
• Nov 29th 2008, 12:26 PM
PrattX
Ok thanks for the help with that but i have another question:

13. sin(sin -11/4)
• Nov 29th 2008, 12:29 PM
skeeter
1/4
• Nov 29th 2008, 12:32 PM
PrattX
how did you get that
• Nov 29th 2008, 12:36 PM
skeeter
do some research and find out why.
• Nov 29th 2008, 12:39 PM
PrattX
i did some research and I dont understand what I'm reading that's why I asked you.
• Nov 29th 2008, 12:45 PM
skeeter
do you understand the concept of an inverse?

a function maps a value x to y

the inverse of that function maps the value y back to x