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# Maths functions... watch

1. ok, quick question...

if...

f(x) = 2x + 1
g(x) = x^2
h(x) = 1 / x

a) find expressions for fg(x) and gf(x)

I got fg(x) = 2x^2 + 1 and gf(x) = 4x^2 + 4x + 2

are these right? if they are I need to:

b) hence find all values of x for which fg(x) = gf(x)

For some reason when i did this I got a strange answer, so its probably wrong.

and finally.

c) show gh(x) = hg(x) for all values of x except x = 0

can anyone help?
2. gf(x) = 4x^2 + 4x + 1

0 = gf(x) - fg(x) = 2x^2 + 4x
x = 0, -2

c)
gh(x) = (1/x)^2 = 1/x * 1/x = 1/x^2 = hg(x)

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Updated: March 15, 2004
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