When to use partial fraction? (1 Viewer)

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1. The problem statement, all variables and given/known data

do we look at the nominator or the denominator? are we trying to separate them? factoring them?

thanks
 

tiny-tim

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Hi myusernameis! :wink:
do we look at the nominator or the denominator? are we trying to separate them? factoring them?
The denominator. And you factor it. :smile:
 
Hi myusernameis! :wink:


The denominator. And you factor it. :smile:
thanks for the answers!

so let's say i have this long equation in denom.

[tex]\frac{1}{(s^2+1)(s^2+4s-12)}[/tex]

i can factor one of them to look like:

[tex]\frac{1}{(s^2+1)(s+6)(s-4)}[/tex]

but then how do I know if I should use A +B or As+B, Cs+D, etc..?
 

tiny-tim

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i can factor one of them to look like:

[tex]\frac{1}{(s^2+1)(s+6)(s-4)}[/tex]
erm :redface: … nooo!
but then how do I know if I should use A +B or As+B, Cs+D, etc..?
sorry, not following you …

for a linear denominator, it's just a number on the top,

for a quadratic denominator, it's a linear top :smile:
 
erm :redface: … nooo!


sorry, not following you …

for a linear denominator, it's just a number on the top,

for a quadratic denominator, it's a linear top :smile:

haha made a mistake... so with that, do i use As+ B?

what if it's (s^2+2)(s^2+3)(s^2+5), ie, several s squares?
 
erm :redface: … nooo!


sorry, not following you …

for a linear denominator, it's just a number on the top,

for a quadratic denominator, it's a linear top :smile:

if was supposed to be a (s+6)(s-2)....
 
each one has a linear top :smile:
ok,

taking this example again: (s^2+2)(s^2+3)(s^2+5)

would it be: 1 = (As+B)/(s^2+2)(s^2+3)(s^2+5) + (Cs+D)/(s^2+2)(s^2+3)(s^2+5) + (Es+F)/(s^2+2)(s^2+3)(s^2+5) ?
 

tiny-tim

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ok,

taking this example again: (s^2+2)(s^2+3)(s^2+5)

would it be: 1 = (As+B)/(s^2+2)(s^2+3)(s^2+5) + (Cs+D)/(s^2+2)(s^2+3)(s^2+5) + (Es+F)/(s^2+2)(s^2+3)(s^2+5) ?
uhh? :confused:

it's 1/(s2+2)(s2+3)(s2+5)

= (As+B)/(s2+2) + (Cs+D)/(s2+3) + (Es+F)/(s2+5)
 
are you a math teacher?
if you don't mind me asking!
 

tiny-tim

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i'm just a little goldfish …

trying to make sense of the bowliverse! :smile:
 

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