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# Help

6 replies to this topic

### #1gary

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Posted 19 May 2005 - 06:09 PM

I can't get the answers to these:

The function x^3-3x+2

find the co-ordinates of a,b,c

find the coordinates of the stationary point d and confirm its nature.

The functions f and g are given as:

f(x) = 4/x-2 and g(x) x+2

what is g(f(x))

Two functions, f and g are definded as follows:

f(x) = x-1 g(x) 1/x^2-1

find g(f(x)

### #2super_diva <3!

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Posted 19 May 2005 - 06:33 PM

I have no clue if these are absolutely right or not, but i've given it a shot. If their wrong then could someone please correct me

f(x) = 4/(x-2) g(x) = (x+2)

f(g(x))

f(x+2) = 4/(x+2)-2

= 4/x

f(x) = (x-1) g(x) = 1/(x -1)

f(g(x))

f(1/(x -1) = 1/x[^2]-1 -1

= 1/x[^2] -2

hope these are ok!

### #3Dave

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Posted 19 May 2005 - 06:34 PM

seem correct to me

If i am not here i am somewhere else

### #4Dave

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Posted 19 May 2005 - 06:36 PM

for the 1st part on finding the point d differentiate the function and equate to zero

then do a nature table to confirm its nature

If i am not here i am somewhere else

### #5gary

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Posted 19 May 2005 - 06:43 PM

I thought it was differentiation just had not seen it like that before.

Thanks.

### #6gary

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Posted 19 May 2005 - 06:47 PM

It is g(f(x)) sorry.

### #7Dave

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Posted 19 May 2005 - 06:59 PM

g(f(x))

=g(x-1)
= 1/ (x-1)^2-1

= 1/ x^2-2x+1-1

1/ x^2 - 2x

If i am not here i am somewhere else

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