Is the function y = x^3 one-to-one? If not, why?

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  • Thread starter mathdad
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In summary, a one-to-one function has a unique output for each input and cannot have two different inputs with the same output. The function y = x^3 is not one-to-one because it can have multiple inputs with the same output. This is due to its odd-degree polynomial nature. A one-to-one function cannot have a horizontal line as its graph. To determine if a function is one-to-one, you can use the horizontal line test or check its algebraic representation for any potential for multiple inputs resulting in the same output.
  • #1
mathdad
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Is the function y = x^3 one-to-one? If not, why?
 
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  • #2
RTCNTC said:
Is the function y = x^3 one-to-one? If not, why?

sketch the graph ... if it passes the horizontal line test, it is 1-1.
 
  • #3
Yes, it passes the horizontal line test and thus 1-1.
 

FAQ: Is the function y = x^3 one-to-one? If not, why?

What does it mean for a function to be one-to-one?

A function is considered one-to-one if each input (x-value) has a unique output (y-value). In other words, no two different inputs can have the same output. This is also referred to as a "one-to-one correspondence" or "injective" function.

Is the function y = x^3 one-to-one?

No, the function y = x^3 is not one-to-one. This is because multiple inputs can result in the same output. For example, both x = 2 and x = -2 have an output of y = 8. This violates the definition of a one-to-one function.

Why is the function y = x^3 not one-to-one?

The function y = x^3 is not one-to-one because it is an odd-degree polynomial function. This means that it has both positive and negative solutions, resulting in multiple inputs having the same output. In general, polynomial functions with an even degree (such as y = x^2) are not one-to-one.

Can a one-to-one function have a horizontal line as its graph?

No, a one-to-one function cannot have a horizontal line as its graph. This is because a horizontal line would have multiple inputs (x-values) with the same output (y-value), which violates the definition of a one-to-one function.

How can you determine if a function is one-to-one?

There are a few ways to determine if a function is one-to-one. One way is to use the horizontal line test, where you draw a horizontal line across the function's graph. If the line intersects the graph more than once, the function is not one-to-one. Another method is to check the function's algebraic representation for any potential for multiple inputs resulting in the same output, such as in the case of a polynomial function with an even degree.

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