I'v quistion on Quadratic Functions

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Homework Help Overview

The discussion revolves around finding the maximum value of the quadratic function f(x) = 125x - 6x² graphically. Participants are exploring the characteristics of quadratic functions and their graphical representations.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Some participants question the original poster's understanding of how to graph quadratic functions and the significance of symmetry in parabolas. Others suggest that finding the roots of the quadratic could provide insights into the maximum or minimum coordinates.

Discussion Status

Participants are actively engaging in clarifying the problem's requirements and discussing the graphical approach to finding the maximum value. There is an emphasis on understanding the concept of maximum in relation to the graph rather than relying solely on algebraic methods.

Contextual Notes

There is a mention of homework rules that discourage providing complete solutions, which may influence the nature of the guidance offered. The original poster is expected to derive the maximum value from the graph rather than using a formula directly.

megatronic
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Homework Statement


Let f(x)= 125x-6x2 find the maximum value of f to four decimal places graphically


Homework Equations


(x)= 125x-6x2


The Attempt at a Solution


Homework Statement



attempt solution:

x=-b+[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=-125+[tex]\sqrt{}125<sup>2</sup>-4(-6)(0)[/tex]/2a

x= 0/-12=0

x=-b-[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=-b-[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=(-125-125)/-12

x=-125/6


Homework Equations





The Attempt at a Solution



 
Last edited:
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Do you know how to make graph for quadratic equations?
 
and also show your attempt otherwise nobody will help you here because of the rules of PF
 
snshusat161 said:
Do you know how to make graph for quadratic equations?

ya I know to make graph for quadratic
 
Ok then, do you realize there is a symmetry of any parabola on either end of its max/min? So if you find the roots of the quadratic, what can you deduce about the coordinates of the max/min from that?
 
megatronic said:

Homework Statement


Let f(x)= 125x-6x2 find the maximum value of f to four decimal places graphically


Homework Equations


(x)= 125x-6x2


The Attempt at a Solution


Homework Statement



attempt solution:

x=-b+[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=-125+[tex]\sqrt{}125<sup>2</sup>-4(-6)(0)[/tex]/2a

x= 0/-12=0

x=-b-[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=-b-[tex]\sqrt{}b<sup>2</sup>-4ac[/tex]/2a

x=(-125-125)/-12

x=-125/6

What you've done is attempt to find the x-intercepts, which is not at all what this problem is asking for. In addition, there is one intercept that you did not find, and the one you found is incorrect.
 
Think what 'maximum' is. Note that maximum does not refer to an x value.

There is a formula to determine the maximum or minimum value of a parabola. Give it a hard think. It'll come to you.
 
Angry Citizen said:
Think what 'maximum' is. Note that maximum does not refer to an x value.

There is a formula to determine the maximum or minimum value of a parabola. Give it a hard think. It'll come to you.
The OP is not supposed to use a formula. He/she is supposed to find the maximum by looking at a graph of the function.
 

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