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Function Help

  • Thread starter physixguru
  • Start date
  • #1
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1. Homework Statement

If f{x + p } = f{x} for all x..then p is called the period of the function.

This part is clear to me.Now the book says...

The period of the function f{ax + b} is b/a.Can someone lead me through.

2. Homework Equations

N/A
 

Answers and Replies

  • #2
tiny-tim
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Hi physixguru! :smile:

hmm :confused: … I think they must mean:
The period of a function f for which f{ax + b} = f{x} for all x is b/a. :smile:

EDIT: ooh … that's not right … thinks … I think they mean the same f, and it's p not b:

The period of f{ax + b} is p/a. :smile:

Hint: put g(x) = f(ax + b). Then … ? :smile:
 
Last edited:
  • #3
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I need the xplanation.
 
  • #4
tiny-tim
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Hi! see edit of previous post.

 
  • #5
HallsofIvy
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If f is a function with period p, that is, if f(x+ p)= f(x) for all x, then f completes one period as x goes from 0 to p. g(x)= f(ax+ b) will complete a period as ax+ b goes from 0 to p. That is, from ax+ b= 0 so x= -b/a, to ax+ b= p so x= (p- b)/a that is a "distance" of (p- b)/a- (-b/a)= p/a- b/a+ b/a. If f has period p, then f(ax+ b) has period p/a, not b/a.
 
  • #6
335
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Thats right...i was cured when ya told me that it was p/a.
thnx all.
 

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