Period of a Graph

quader

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Sep 25, 2014
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Write down the period of the graph of 123.jpg

and also the coordinates of a maximum value of y.




So, I thought the period was 360 or 2Pi divided by the angle, but I'm not sure what to do here.
 
The period of cos(x) is \(\displaystyle 360\) degrees (it is hard to do this in degrees rather than radians!) so the period of cos(ax) is \(\displaystyle 360\) divided by a. But this problem has \(\displaystyle cos^2(x)\). cos(x+ 180)= -cos(x) so that \(\displaystyle cos^2(x+ 180)= cos^2(x)\).
 
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Okay yeah, I thought the answer was 180. How do I go about the maximum value question?
 
No, the period is NOT 180 degrees and I did not say it was!

As for the maximum, a fraction, with a fixed numerator will be largest when the denominator is smallest. What is the smallest possible value of \(\displaystyle 1+ cos^2(2x)[/itex]?\)
 
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