• Jun 18th 2008, 12:33 PM
Darkhrse99
I'm finding the exact values of the following expressions.

1. $sin(\frac{-7pi} {3})$ = $\frac{\sqrt3}{2}$

2. $sec(\frac{-21pi}{4})$= $\frac{-\sqrt1}{2}$

3. $cot(\frac{25pi}{2})$=Undefined

4. $csc(\frac{-101pi}{6})$= $-1$

5. $cos({-126Pi})$= Undefined

Thank You
Jason
• Jun 18th 2008, 12:41 PM
Moo
Quote:

Originally Posted by Darkhrse99
I'm finding the exact values of the following expressions.

1. $sin(\frac{-7p} {3})$ = $\frac{\sqrt3}{2}$ << SiMoon says : eh.. -7pi/3=-pi-pi/3, that is to say it's in the 3rd quadrant ---> sine is negative

2. $sec(\frac{-21p}{4})$= $\frac{-\sqrt1}{2}$ << SiMoon says : it's rather $-\sqrt{\frac 12}=-\frac{2}{\sqrt{2}}$ eh ? Check the code =)

3. $cot(\frac{25p}{2})$=Undefined << SiMoon says : is 0 undefined ? $\cot=\frac{\cos}{\sin} \quad \quad \frac{25 \pi}{2}=6*(2 \pi)+ \frac{\pi}{2}$ ---> ...

4. $csc(\frac{-101p}{6})$= $-1$ << SiMoon says : I find -2

5. $cos({-126P})$= Undefined << SiMoon says : I find 1

Thank You
Jason

(Tongueout)
• Jun 18th 2008, 12:49 PM
Chris L T521
Quote:

Originally Posted by Darkhrse99 http://www.mathhelpforum.com/math-he...s/viewpost.gif
I'm finding the exact values of the following expressions.

1. http://www.mathhelpforum.com/math-he...9153e5ad-1.gif = http://www.mathhelpforum.com/math-he...047f43ec-1.gif << SiMoon says : eh.. -7pi/3=-pi-pi/3, that is to say it's in the 3rd quadrant ---> sine is negative. Chris says it's in the 4th quadrant. -7pi/3=-2pi-pi/3 -----> sine is still negative (As Moo correctly stated)

2. http://www.mathhelpforum.com/math-he...d753fd61-1.gif= http://www.mathhelpforum.com/math-he...695c9f52-1.gif << SiMoon says : it's rather http://www.mathhelpforum.com/math-he...33e7f39d-1.gif eh ? Check the code =)

3. http://www.mathhelpforum.com/math-he...05ff852a-1.gif=Undefined << SiMoon says : is 0 undefined ? http://www.mathhelpforum.com/math-he...91e4e883-1.gif ---> ...

4. http://www.mathhelpforum.com/math-he...ec74b973-1.gif= http://www.mathhelpforum.com/math-he...d1d82c88-1.gif << SiMoon says : I find -2.

5.http://www.mathhelpforum.com/math-he...4886f46f-1.gif= Undefined << SiMoon says : I find 1

Thank You
Jason

(Sun)
• Jun 18th 2008, 12:53 PM
Moo
Quote:

Originally Posted by Chris L T521
(Sun)
[/I]

Like I said, $7=3+1$ !!!
:p

Hey, how did you quote what I quoted ?
• Jun 18th 2008, 12:55 PM
Chris L T521
Quote:

Originally Posted by Moo
Like I said, $7=3+1$ !!!
:p

Hey, how did you quote what I quoted ?

What I did was a little something called copy and paste. (Sun)

When I quoted you to post my response. I saw just this : (Tongueout)

However, I thought I could copy what you quoted and then put it in the quote tags...and it worked... :D
• Jun 18th 2008, 01:03 PM
Moo
Quote:

Originally Posted by Chris L T521
What I did was a little something called copy and paste. (Sun)

When I quoted you to post my response. I saw just this : (Tongueout)

However, I thought I could copy what you quoted and then put it in the quote tags...and it worked... :D

When I copy & paste, it doesn't copy the latex stuff :(
• Jun 18th 2008, 01:08 PM
Darkhrse99
For #2. the point are $-\frac{\sqrt1}{2} and \frac{1}{2} = \frac{1}{y}$ Which gives the answer $\frac{-\sqrt1}{2}$, Right?
• Jun 18th 2008, 04:31 PM
Darkhrse99
I don't see how you get -2 for the 2nd problem?