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#1

$Old$ January 4th, 2009, 02:45 PM

magentarita $magentarita is offline$

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$Default$ Angle Theta

As angle θ increases from π radians to 2pi radians, the cosine of θ

(1) increases throughout the interval
(2) decreases throughout the interval
(3) increases, then decreases
(4) decreases, then increases

Please, explain your answer not just select one form the choices.

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#2

$Old$ January 4th, 2009, 02:59 PM

Simplicity $Simplicity is offline$

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Look at this cosine graph:

What happens when theta changes from $\pi$ to $2\pi$ ?

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#3

$Old$ January 4th, 2009, 03:03 PM

magentarita $magentarita is offline$

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$Default$ it gets...

Quote:

Originally Posted by Air $View Post$

Look at this cosine graph:

What happens when theta changes from $\pi$ to $2\pi$ ?

Theta increases then increases???

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#4

$Old$ January 4th, 2009, 03:09 PM

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Here is a graph of $y = \cos{x}$ for the interval $[-2\pi, 2\pi]$ . http://upload.wikimedia.org/wikipedi...px-Cos.svg.png

Between $\pi$ and $2\pi$ it can be seen that $y = cos{x}$ is always increasing (except at the exact points of $\pi$ and $2\pi$ , which are stationary points)

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#5

$Old$ January 4th, 2009, 03:18 PM

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Quote:

Originally Posted by magentarita $View Post$

Theta increases then increases???

Yes, that is correct. The only option which matches that is option (1).

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$Old$ January 6th, 2009, 12:00 AM

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Thank you both for your great help.

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