Solving problems in function notation

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Homework Help Overview

The problem involves function notation and seeks to determine the value of g(3) given specific function properties and an equation relating g(2x+1) to g(x). The subject area is primarily focused on function transformations and evaluations.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the interpretation of the function g(2x+1) and its relation to g(x). There is an exploration of how to express the input 3 in terms of the form 2x+1, leading to questions about the appropriate value of x to use.

Discussion Status

The discussion has progressed with participants offering insights into how to manipulate the equation to find g(3). Some guidance has been provided regarding substituting specific values into the equation, and there is a recognition of the logical steps involved in reaching a solution.

Contextual Notes

Participants note that the problem is derived from a PSAT workbook, which may impose certain constraints or expectations on the problem-solving approach. There is an acknowledgment of the initial confusion regarding the transformations involved in the function.

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Homework Statement


Given that:
g (1)=3
g (2x+1)=4g (x)+x+1

Find g (3)

Homework Equations


The awnser is 14. (Taken out of a PSAT workbook)

The Attempt at a Solution


I assume that g(2x+1) refers to a series of transformations (horizontal dilation, up 1) of g(x)
Once g(x) is found, g(3) can easily be solved. The problem is, that I have no idea how to find it.
 
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The second equation tells you how to find [itex]g(2x + 1)[/itex] if you already know [itex]g(x)[/itex].

For which value of [itex]x[/itex] do you already know [itex]g(x)[/itex]?
 
Daringpear said:

Homework Statement


Given that:
g (1)=3
g (2x+1)=4g (x)+x+1

Find g (3)

Homework Equations


The awnser is 14. (Taken out of a PSAT workbook)

The Attempt at a Solution


I assume that g(2x+1) refers to a series of transformations (horizontal dilation, up 1) of g(x)
Once g(x) is found, g(3) can easily be solved. The problem is, that I have no idea how to find it.
To me it appears you think a little bit too complicated.
Can you write ##3## as ##2x+1## and what does it tell you about ##x##?
 
Ah! Your suggestions make sense!

When substituting x for one,

g(2(1)+1)=4g(1)+1+1
g(3)=4(3)+2
g(3)=12+2
g(3)=14
 

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