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Basic function question

  • Thread starter greenneub
  • Start date
  • #1
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Homework Statement


I'm not sure what I'm doing wrong here.


Homework Equations


f(t) = t/(t+1)2 find f(1/t)


The Attempt at a Solution


f(1/t) = 1/(t/(t+1)2)

= ((t+1)2)/t

= (t2 + 2t +1)/t


The answer in my book says it's t/(t+1)2, the original function. Is this an error?
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
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Hi greenneub! :smile:
f(t) = t/(t+1)2 find f(1/t)

The Attempt at a Solution


f(1/t) = 1/(t/(t+1)2)
No, that's 1/f(t) …

you want f(x) where x = 1/t …

in other words, replace t by 1/t everywhere it occurs in t/(t+1)2 :wink:
 

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