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Homework Help: Cos^2(pi/4) help

  1. Jul 16, 2012 #1

    Why does this equal to 1/2? Doesn't Cos(Pi/4)= √2/2 ?

  2. jcsd
  3. Jul 16, 2012 #2
    What is (√2/2)^2?
  4. Jul 16, 2012 #3


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    [itex]\cos^2 \frac{\pi}{4}[/itex]
    [itex]= \left(\cos \frac{\pi}{4}\right)\left(\cos \frac{\pi}{4}\right)[/itex]
    [itex]= \left(\frac{\sqrt{2}}{2}\right)\left(\frac{\sqrt{2}}{2}\right)[/itex]
    [itex]= ?[/itex]
  5. Jul 16, 2012 #4
    Opps! Haha, thank you both.
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