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# quick c1 question Watch

1. why does the book start using

g(x) and h(x) instead of f(x)?

and why dont they just say y= x^2, they say f(x) = x^2 ??
2. Just think of them as names, it's like when your teacher started giving you simultaneous equations in 'a' and 'b' instead of 'x' and 'y' just to keep you on your toes.
3. but remember

f(x)=3x+2 is same as y=3x+2 (most of the time)

the same way some books use 2a + 3b = 15 .....
they are just names
They just want you to get used to name them in other ways for you be prepared for c2 c3 ....
4. (Original post by jayseanfan)
why does the book start using

g(x) and h(x) instead of f(x)?

and why dont they just say y= x^2, they say f(x) = x^2 ??
f(x), g(x), h(x) are all functions of x. They are often used to describe a different function if f(x) has already been used in a question of something.

f(x) and y are interchangeable. It's just different notation y=x is the same as f(x)=x is the same as f:x-> x.
5. (Original post by jayseanfan)
why does the book start using

g(x) and h(x) instead of f(x)?
Usually when you only have one function, its usually represented as as f(x), which is a function of x, or with respect to x. g(x) and h(x) are the same thing, both are functions of x, but using different letters like g and h makes things clearer when you have more than one function. You can use any letter, so things like a(x) or z(x) would also be valid at representing functions of x.

If we state f(x) = 3x + 2, then you can't also say f(x) = 2x + 1, as you'd be saying f(x) is 2 functions and you don't know which one is which.

If we say f(x) = 3x + 2 and g(x) = 2x + 1, then when doing the maths its much clearer and you've got no contradictive-ness.

If theres only one function and the book is calling it g(x) or h(x), then the book is trying to make things seemingly complicated. You can't expect everything to require no thought!

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Updated: December 4, 2010
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