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Maximum and chnage of sign of a function

  1. May 27, 2009 #1
    Guys Can anyone help me in this? I need a function (cos or sin) maximum at 7Pi/4 and at the same time changes sign under phi->phi+Pi with 0< phi< 2Pi....Thank you
  2. jcsd
  3. May 27, 2009 #2
    Do you know how to shift and stretch functions?
  4. May 28, 2009 #3
    Yes of course I do and u can find a function that is maximum at 7pi/4 but the problem is how to also make it change sign under phi->phi+Pi...
  5. May 28, 2009 #4


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    [tex]sin(x+ \pi)= -sin(x)[/tex]

    That's no problem at all!
  6. May 28, 2009 #5
    Thanks HallsofIvy but the maximum of the function should be at [tex] \phi=\frac{7\pi}{4}[/tex]. I guess the function should be [tex] \sin (\phi-\frac{\pi}{4}) [/tex]
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