(Real functions and equations) How to select points for a graph.

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Discussion Overview

The discussion revolves around the selection of points for graphing various types of functions, specifically quadratic, square-root, and inverse variation functions. Participants explore methods for identifying key points such as vertices and intercepts, and express uncertainty regarding the selection of additional points for accurate graph representation.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses uncertainty about how to select points for graphing quadratic, square-root, and inverse variation functions, suggesting specific base points for these functions.
  • Another participant proposes a method for selecting points for a square-root function by finding values of x that yield perfect squares, and for quadratic functions by reflecting points across the axis of symmetry.
  • A third participant requests clarification on the notation used in the mathematical expressions and indicates a lack of understanding of the proposed methods.
  • A later reply clarifies the notation and provides an alternative method for generating points for the square-root function based on a different form of the function.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best methods for selecting points, as there are differing approaches and some participants express confusion regarding the explanations provided.

Contextual Notes

Some participants indicate limitations in their understanding of mathematical symbols and notation, which may affect their ability to follow the proposed methods for selecting points.

Kyriakos1
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When I am given a function quadratic, square-root and inverse variation I am often uncertain as to how to select my points to graph the function. Usually I can find my vertex easily enough and y and x intercepts if any but otherwise I don't know how to select my points. Are there base points for each function? Such as (0,0), (1,1), (4,2), (8,2.8) for a function of square-root or (0,0), (1,1), (2,4), (-1,1), (-2,4) for a quadratic function.
 
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If I am given a function of the form:

$$f(x)=a\sqrt{g(x)}+b$$

Then, I will find $x=x'$ such that:

$$g(x')=n^2$$ where $$n\in\mathbb{N_0}$$

Then I plot the points:

$$(x,y)=(x',an+b)$$

If I am given a function of the form:

$$f(x)=a(x-h)^2+k$$

I let $$x=h+n$$ where $$n\in\mathbb{N_0}$$, and then for each point, reflect it across the axis of symmetry. You will get the set of points:

$$(x,y)=(h\pm n,an^2+k)$$
 
I thank you for answering and I do not mean to sound ungrateful but I don't really understand your explanation. I do not understand these symbols: n ∈ N 0 x′.
Also I have learned the square root-function as f(x)=a\sqrt{b(x-h)} + k and am unsure how to use f(x)=ag(x)−−−−√+b. Perhaps you can dumb it down a notch.
 
The statement $$n\in\mathbb{N_0}$$ means that n is a natural number including zero, that is:

$$n\in\{0,1,2,3,\cdots\}$$

If you are given:

$$f(x)=a\sqrt{b(x-h)}+k$$

then set:

$$b(x-h)=n^2\implies x=\frac{n^2}{b}+h$$

which generates the points:

$$\left(\frac{n^2}{b}+h,an+k\right)$$
 

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