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Any maths geniuses Help maths

I cant do this question:


(4x^2-1)/((x+2)(X^2+1)

I've got up to 3/(x+2) but how do I find the other partial fraction?
anyone?????
Reply 2
Avatar for mik1a
mik1a
10
That's not a question, it's an expression! What is the question?

Maybe I'm not enough of a genius...
Reply 3
Avatar for Daz0101
Daz0101
1
Original post by Mathshelp>
I cant do this question:


(4x^2-1)/((x+2)(X^2+1)

I've got up to 3/(x+2) but how do I find the other partial fraction?


you need to state what your trying to do as you have just gave an exprestion with out any context if your trying to make 2 fractions you could have (4x-1)/(x^2+2x-1) -(4x^2-1)/2
Reply 4
Avatar for dnr_23
dnr_23
9
=
3/(x+2) - 1/((x^2)+1)
Reply 5
Avatar for dnr_23
dnr_23
9
this is my method:

4x^2 -1/(x+2)(x^2 +1) = A/(x+2) + B/(x^2 +1)

4x^2 -1 = A(x^2 +1) + B(x+2)

Let x=-2 (this will cancel out B)

15=5A
A=3

Let x=1

3=2A +3B
3=2(3) +3B
-3=3B
B=-1

Sub back into 4x^2 -1/(x+2)(x^2 +1) = A/(x+2) + B/(x^2 +1)
to get

3/(x+2) - 1/(x^2 +1)
Reply 6
Avatar for dnr_23
dnr_23
9
Original post by Daz0101
you need to state what your trying to do as you have just gave an exprestion with out any context if your trying to make 2 fractions you could have (4x-1)/(x^2+2x-1) -(4x^2-1)/2


lol he was asking about partial fractions, took me a while to realise it too

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