Is this function correct? (Not a homework Question)

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Discussion Overview

The discussion revolves around the correctness of a mathematical function and its evaluations. Participants analyze the functions defined by the user and provide feedback on the calculations involved.

Discussion Character

  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • The original poster presents a function f(x)=2x+3 and subsequent functions g(f) and w(g), along with specific evaluations.
  • Some participants confirm that the evaluations are correct, provided that g(f(x)) and w(g(f(x))) are interpreted correctly.
  • One participant elaborates on the functions, stating that g(f(x)) simplifies to 2x+5 and w(g(f(x))) results in a polynomial expression, which they evaluate at x=2 to yield 84.

Areas of Agreement / Disagreement

There appears to be general agreement among participants regarding the correctness of the calculations, though the original poster's notation and intent are clarified by others.

Contextual Notes

Some assumptions about the notation and the intended functions may not be explicitly stated, leading to potential ambiguity in interpretation.

QuantumPixel
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I was bored and decide to make a function (yes, i am a bit weird). So I came up with this:

f(x)=2x+3
g(f)= f+2
w(g)=g2+3

x=2

f(2)=4+3
f(2)=7
g(7)=7+2
g(7)=9
w(9)=81+3
w(9)=82

Is those working outs correct or not? If it isn't could you tell me where i got it wrong?
 
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As long as you mean g(f(x)) and w(g(f(x))), then you have the right answer
 
Yes, what you have is correct. More generally, with f(x)= 2x+ 3, g(x)= x+ 2, and [itex]w(x)= x^2+ 3[/itex], [itex]g(f(x)= (2x+ 3)+ 2= 2x+ 5[/itex] and [itex]w(g(f(x)))= (2x+ 5)^2+ 3= 4x^2+ 20x+ 28[/itex].

Evaluating that at x= 2 gives 4(4)+ 20(2)+ 28= 16+ 40+ 28= 84.
 
Gackhammer said:
As long as you mean g(f(x)) and w(g(f(x))), then you have the right answer

HallsofIvy said:
Yes, what you have is correct. More generally, with f(x)= 2x+ 3, g(x)= x+ 2, and [itex]w(x)= x^2+ 3[/itex], [itex]g(f(x)= (2x+ 3)+ 2= 2x+ 5[/itex] and [itex]w(g(f(x)))= (2x+ 5)^2+ 3= 4x^2+ 20x+ 28[/itex].

Evaluating that at x= 2 gives 4(4)+ 20(2)+ 28= 16+ 40+ 28= 84.

Thanks for your time on here! :-)

-QuantumPixel
 

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