Maximum and chnage of sign of a function

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    Function Maximum Sign
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Discussion Overview

The discussion revolves around finding a mathematical function, specifically a sine or cosine function, that achieves a maximum at \( \frac{7\pi}{4} \) and also changes sign under the transformation \( \phi \to \phi + \pi \) within the interval \( 0 < \phi < 2\pi \).

Discussion Character

  • Mathematical reasoning, Technical explanation

Main Points Raised

  • One participant requests assistance in identifying a function that meets specific criteria regarding its maximum and sign change.
  • Another participant inquires about the ability to shift and stretch functions, suggesting familiarity with function transformations.
  • A participant acknowledges that it is possible to find a function with a maximum at \( \frac{7\pi}{4} \) but highlights the challenge of ensuring it also changes sign under the specified transformation.
  • A later reply states that the transformation \( \sin(x + \pi) = -\sin(x) \) can be utilized, implying a potential solution exists.
  • One participant expresses gratitude and suggests that the function could be \( \sin(\phi - \frac{\pi}{4}) \) to achieve the desired maximum.

Areas of Agreement / Disagreement

Participants do not reach a consensus on a specific function that satisfies both conditions, and multiple viewpoints regarding the approach to the problem are presented.

Contextual Notes

The discussion does not clarify the assumptions or specific transformations applied to the functions, nor does it resolve the mathematical steps necessary to confirm the proposed solutions.

Physicslad78
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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
 
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Do you know how to shift and stretch functions?
 
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...
 
[tex]sin(x+ \pi)= -sin(x)[/tex]

That's no problem at all!
 
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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