partial Fractions

[unseendamageUK]

hello everyone, im having trouble sorting out a partial fraction which has a cubed on the bottom.

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

Not sure how to deal with the cubed bit :S
My A-level maths exam is tomorrow.

I know ive left it late but meh.

HELP ME

[billeh!]

F o i l my child!

[Kilgannon]

try this

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

[piranhamatt2]

For the Cubed bit do

(1-2x)(1-2x)(1-2x)

Also C3 exam much?

[unseendamageUK]

[QUOTE=Kilgannon;22605540]try this

(1-3x)/(1-2x)(1-2x)(1-2x)[/QUOTE]

do you know what a partial fraction is?

[piranhamatt2]

[QUOTE=unseendamageUK;22605555]do you know what a partial fraction is?[/QUOTE]

Wait isnt that the replacing 1-2x with a letter, or something?

So like L^3

[chaz13]

Which is

(1-3x)/(1-8x^3-6x)

[unseendamageUK]

partial fraction is when you take (1-3x)/(1-2x)^3 and split it into 3 fractions

A/x + B/y + C/z

atm x.y and z are what i need to find
i was thinking (1-2x),(1-2x)^2 and (1-2x)^3
but im not sure really

[Manta Ray]

[QUOTE=unseendamageUK;22605688]partial fraction is when you take (1-3x)/(1-2x)^3 and split it into 3 fractions

A/x + B/y + C/z

atm x.y and z are what i need to find
i was thinking (1-2x),(1-2x)^2 and (1-2x)^3
but im not sure really[/QUOTE]

this man is right.

c4 is going to rape me

[Robbobin]

throughout core 4 I [I]never[/I] saw a question like this. you can't solve it by equating coefficients or by substituting values so I have no fucking idea. Partial Fractions are almost a piece of fucking piss.

[J_Rambo]

A proper fraction which has a repeated linear factor in the denominator,

q(x)/(x-a)^3, has partial fractions of the form

A/(x-a) + B/(x-a)^2 + C/(x-a)^3

Copied from a text book.

[unseendamageUK]

[QUOTE=Robbobin;22612766]throughout core 4 I [I]never[/I] saw a question like this. you can't solve it by equating coefficients or by substituting values so I have no fucking idea. Partial Fractions are almost a piece of fucking piss.[/QUOTE]
Yeh, partial fractions are simple, but ive never seen any partail fraction like that so i was unsure, as was most of our class.

But its fine cause there were none of those in the exam

[Kalinium]

[img]http://www4c.wolframalpha.com/Calculate/MSP/MSP41119b3e49egh48c5720000314a3dg16hgab3ce?MSPStoreType=image/gif&s=28&w=293&h=40[/img]

[img]http://www4c.wolframalpha.com/Calculate/MSP/MSP259319b3ddia08fgif5f00003cfe319884790b5h?MSPStoreType=image/gif&s=3&w=238&h=20[/img]

x = 1/2 implies c = -1/2

A = 0 (comparison of x^2 terms)

and so B = 3/2

so:

[img]http://www4c.wolframalpha.com/Calculate/MSP/MSP83519b3e2acid0685b000002h45a4fig6gce528?MSPStoreType=image/gif&s=27&w=229&h=48[/img]

[Megaket]

What the Hell people, why do you make my brain hurt so much?!

[Number-41]

-snip-

I suck at math