Math Is Fun Forum

leopragi

Member

Registered: 2016-05-22

Posts: 3

Function Confusion

If function is single valued. It will not give back 2 or more results for the same input.

f(x) = sqrt( x ) for example is also must not be a function right? If i plug in 2, f(2) = +2 or -2

In most book i found similar to this...

Mathegocart

Member

Registered: 2012-04-29

Posts: 2,226

Re: Function Confusion

If function is single valued. It will not give back 2 or more results for the same input.

f(x) = sqrt( x ) for example is also must not be a function right? If i plug in 2, f(2) = +2 or -2

In most book i found similar to this...

No.
https://www.desmos.com/calculator most graphs only show the positive root.

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leopragi

Member

Registered: 2016-05-22

Posts: 3

Re: Function Confusion

If no, then in some book that have said to Find domain for given function,  like f(x) = sqrt(4-7x), if x=0, then f(x)=-2 or +2

zetafunc

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Registered: 2014-05-21

Posts: 2,432

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Re: Function Confusion

It is a function. By convention, the square root function gives us non-negative values only, i.e.

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Last edited by zetafunc (2016-05-31 03:01:20)

thickhead

Member

Registered: 2016-04-16

Posts: 1,086

Re: Function Confusion

It is the tussle between mathematics and computation. Mathematics gives all possible values.Computation however if not precise and unique give rise to unwanted complications in the result.

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