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November 13th, 2016, 01:20 PM  #1 
Member Joined: Nov 2016 From: Ireland Posts: 54 Thanks: 2  Another functional disfunction
If r(t) = 2t+3 and s(t) = 7t^2  t find : s(r(t)) s(r(t)) = s(2t + 3) = 7(2t + 3)^2 − (2t + 3) <<<{Where is this guy coming from?} = 7(4t^2 + 12t + 9) − (2t + 3) = (28t^2 + 84t + 63) − (2t + 3) = 28t^2 + 82t + 60 I can understand the first (2t + 3)^2 but surely that should cover the function s. Why the need for the 2t + 3? Last edited by Kevineamon; November 13th, 2016 at 01:23 PM. 
November 13th, 2016, 01:53 PM  #2 
Global Moderator Joined: Dec 2006 Posts: 16,376 Thanks: 1174 
Each "t" in "s(t) = 7t^2  t" is to be replaced with "2t + 3".

November 13th, 2016, 02:03 PM  #3 
Member Joined: Nov 2016 From: Ireland Posts: 54 Thanks: 2 
Ahhh well there we go. Thanks Skipjack.


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disfunction, functional 
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