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C3 - functions

I've got a problem with doing C3 functions questions. For example, one of the questions asks to prove that

f(x) = \frac{1}{x+1}, x>3

, knowing that

f: x

\frac{2(x-1)}{x^2-2x-3} - \dfrac{1}{x-3}, x>3

. I completely don't know how to approach a question like that. :confused:

What does this arrow mean? I can't find anything about it in textbook... :eek:

Thanks,
Draggy

Reply 1

marcus2001

The arrow means greater than, imagine it to be like a pacman that wants to eat the biggest number.

No worries,
Marcus

Reply 2

Draggy

Dude, I don't mean that arrow... :tongue:

f: x -> is the one I don't get.

Reply 3

Hopple

The arrow (well, the whole 'sentence') means f is mapping x to that expression, for x>3. It's basically asking you to combine those two fractions into 1/(x+1)

Reply 4

jembishop

the arrow can be read as f(x)=such and such

For this one try factorising the denominator of the first fraction

Reply 5

Skilled

factorise the bottom then solve as a normal fraction seeing whats in common (the spoiler below is what you should get) but try and work it out urself . (hint: (x-3)(x+1) is going to be the denominator above which you will have to minus), once you do that, then you should get the answer.

SPOILER
SPOILER
SPOILER

(2x-2-x-1)/(x+1)(x-3)

Reply 6

boromir9111

factorise that shizzle!

Reply 7

Draggy