Maths - what does f(x) mean?

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chanandler
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#1
Report Thread starter 16 years ago
#1
I need to know what f(x) means and why we use it in maths? I'm really stuck.
Thanks in advance
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Mustard-man
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#2
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#2
'function of x'
f(x) basically means y, and f'(x) means dy/dx
The x can have a value, so for example, f(x) = 2x + 1, then f(1) = 3

that is as good as I can explain it!!!
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Mustard-man
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#3
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#3
O, and f(x) is the 'range' (range and domains come in at A2 (ocr spec.))
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Sasuke!
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#4
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#4
f(x) is just something that is done to "x", its a function
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*River
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#5
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#5
(x) is the basic equation of the graph, say, x² + 4x +4.

The F is what you are doing to it, eg translating it up 2, or stretching it etc. There are equations for this but I've forgotten them!
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Niaya
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#6
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#6
(Original post by gordon2002)
'function of x'
f(x) basically means y, and f'(x) means dy/dx
The x can have a value, so for example, f(x) = 2x + 1, then f(1) = 3

that is as good as I can explain it!!!
Tbh thats about as good as most people would be able to do and i didnt know that f'(x) was dy/dx
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Chewwy
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#7
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#7
remember the little function boxes you did when you were like 10. x goes in, f(x) comes out. the function could be, say, adding 5, dividing by two... whatever.
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AlphaNumeric
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#8
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#8
(Original post by heninacoop)
(x) is the basic equation of the graph, say, x² + 4x +4.

The F is what you are doing to it, eg translating it up 2, or stretching it etc. There are equations for this but I've forgotten them!
Completely wrong. As Chewwy says, x goes in, f(x) comes out. You can use g(x), h(x), Ø(x), Ω(x), Bob(x), Ostrich(x), anything you like. The letter, symbol or even word before the (x) is simply a way of allowing you to know which function it is you are talking about. You can define f(x) to be anything you like, the "f" label is irrelevant of what the function is.

The letter within the brackets is the variable. You can have multiple variables too, like f(x,y), H(x,y,t) or anything you like really (but not repeated letters!).
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PIPSarah
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#9
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#9
f(x) is the gradient function isnt it? you use it to find gradients using differentiation?
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Ads.
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#10
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#10
(Original post by PIPSarah)
f(x) is the gradient function isnt it? you use it to find gradients using differentiation?
No you are wrong. READ the posts above before replying.f'(x) would be the gradient
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button16
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#11
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#11
remember the little function boxes you did when you were like 10. x goes in, f(x) comes out. the function could be, say, adding 5, dividing by two... whatever.
That's great you deserve some rep I've been having trouble understanding this.
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hawaiian_angel
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#12
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#12
(Original post by chanandler)
I need to know what f(x) means and why we use it in maths? I'm really stuck.
Thanks in advance

f(x) just means a 'function' of 'x',
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shaneal
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#13
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#13
i need help
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조남호
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#14
Report 4 years ago
#14
I'm Korean high school student.and i have more questions after reading all the replys...f(x) means function basically as we all learned...but when we think about the polynomial,the question says 'the polynomial f(x)=3x 4....'I want to ask that f(x)'s meaning...
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Galibmehedijami
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#15
Report 3 years ago
#15
If f(x+4)=4x then find f(x)?
Can anyone explain how its done?
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LowIQ
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#16
Report 3 years ago
#16
(Original post by Galibmehedijami)
If f(x+4)=4x then find f(x)?
Can anyone explain how its done?
I may be wrong but what you want to do is to do the reverse of the change in the input x. Eg. in this function it shows that 4 is added to the input as shown with f(x+4) but to get f(x), you do the opposite so subtract 4 to get back to the original input, x. Therefore you get f((x+4) - 4) which is f(x) as +4-4 is 0. Thus with the 4x, the x here would be substituted for (x-4) which results with 4(x-4) and if you expand that, you get 4x-16. So f(x)=4x-16.
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Lighting girl
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#17
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#17
Ya me to can someone help us
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Lighting girl
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#18
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#18
But how I am still confused how does it become a 3
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Lighting girl
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#19
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#19
What do u mean by f means functions
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Harry14
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#20
Report 2 years ago
#20
It is a functions question where you have to substitute
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