Any One Do A2 Maths C4?? - HotUKDeals
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Any One Do A2 Maths C4??

wazb Avatar
7y, 11m agoPosted 7 years, 11 months ago
the question is

given that f(x) = 2xcubed + 9xsqaured + 10x + 3


part a is easy just says show that -3 is a root of F(x), if you sub -3 in as x you get 0.

but part b says

Express 10/f(x) as partial fractions

now when theres a quadractic as the denominator thats fine i can split them up, but i dont know how to factorise that cubic equation to get 3 seperate fractions, any help?? been stuck on this all day.
wazb Avatar
7y, 11m agoPosted 7 years, 11 months ago
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#1
15 years ago i coulda told you but, got drunk far too many times to remember all this sry . and gl
1 Like #2
Mate you've got the factor, -3, so divide the cubic by (x+3) and get a quadratic.

I only do AS but I'm guessing that would work.
banned#3
^ maybe
and
Express 10/f(x) as partial fractions

Are you sure its 10 divided by the f(x) don't usually see that sort of question.
1 Like #4
LOL, i can help -
you said -3 is a root of x, right?
so immediately you can factorise to become (x+3)(whatever)
Use long division or other to get the "whatever". It will DEFINATELY work becos -3 will flush in perfectly -its a root.
EDIT: Ahh someone above said it already :D
#5
I'm no help, just thought you should know i hate your avatar. :p

Good luck finding the answer.
#6
Pryd4 i think you may be right, figures i got a E in AS, thats defiantly the question.
banned 1 Like #7
Hmm

so using the factor -3?

if you do this you got it yeah?

http://img132.imageshack.us/img132/6805/lolkq5.jpg
#8
Artonox
LOL, i can help -
you said -3 is a root of x, right?
so immediately you can factorise to become (x+3)(whatever)
Use long division or other to get the "whatever". It will DEFINATELY work becos -3 will flush in perfectly -its a root.
EDIT: Ahh someone above said it already :D


Beat you to it :p
#9
yhhh i did it thanks guys,

i ended up with after findind a.b.c

1/x+3 + 8/2x+1 - 5/x+1

rep left for the help
banned#10
Artonox
LOL, i can help -
you said -3 is a root of x, right?
so immediately you can factorise to become (x+3)(whatever)
Use long division or other to get the "whatever". It will DEFINATELY work becos -3 will flush in perfectly -its a root.
EDIT: Ahh someone above said it already :D


Its a factor of X not a root i think
#11
wazb
yhhh i did it thanks guys,

i ended up with after findind a.b.c

1/x+3 + 8/2x+1 - 5/x+1

rep left for the help


No problem :thumbsup:
#12
Conscept
Its a factor of X not a root i think




its defo a root, question says ahow that -3 is a root of f(x)
#13
Conscept
Its a factor of X not a root i think


lol being nitpicky now arn't we :-D
I say root because if you draw the graph, it will intersect y=0 at 3 places - they are called roots.
Or we could call them your way, namely a factor of f(x) because it goes in with no remainders, like 2 is a factor of 4.
banned#14
wazb
its defo a root, question says ahow that -3 is a root of f(x)

Oh my bad, haha silly me :)

Least you got it done :)

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