x2 and x
Summary
Students will compare and contrast the graphs of y= x2 and y=
x.
Goals
1. Students will look at x squared and x as functions, and for
which values of x one function value is greater than the other.
Materials
Handouts
Duration
50 minutes
Keywords
Compare and Contrast Functions
Cubic Functions
Full Class Discussion
Linear Functions
Production of Graphs
Quadratic Functions
Activity Plan:
1. Have students graph x squared and x. If more advanced, include x cubed.
Some students may need help squaring numbers in between (-1,0) and
(0,1). (Handout Page 1)
2. For discussion (Handout Page 2):
When is one function greater than the other?
When are they the same?
What will happen as x goes to infinity or negative infinity?
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Handout: x2 and x
(Page 1)
Name: _____________________________________Date:_________
Graph these two functions below:
A: y= x
B: y= x2
© Tufts University, 2009
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Handout: x2 and x
(Page 2)
Name: _____________________________________Date:_________
Think about the functions you just graphed:
A: y= x
B: y= x2
When is y the same for function A and function B?
When is y larger for function A than it is for function B? Why?
What do you think will happen, as x gets larger? What if x is 10? What if x
is 100?
How can we prove to somebody else what will happen as x gets larger and
larger?
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