SUNGHWA C.

asked • 04/05/16

Give an example of a cubic (degree 3) function that is bijective. Explain why it is bijective. Give an example of a cubic (degree 3) function that is not biject

Give an example of a cubic (degree 3) function that is bijective. Explain why it is bijective. Give an example of a cubic (degree 3) function that is not bijective. Explain why it is not bijective.

2 Answers By Expert Tutors

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Andrew M. answered • 04/06/16

Tutor
New to Wyzant

Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors

John G.

-x3 is still bijective.  It's just x3 reflected over the x-axis. 
f(-1) = -(1)3 = -1, not 1
 
Try adding more terms to get one that's not a bijection.
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04/06/16

John G.

And now I have a typo.  Should say f(1)
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04/06/16

Andrew M.

John G., 
I had already realized that and was fixing it when you wrote your comment.  But thank you.  I appreciate it.
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04/06/16

John G. answered • 04/05/16

Tutor
4.8 (52)

Understanding math via the real world.

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