PDA

View Full Version : factoring problem


EvLer
Oct3-05, 11:50 PM
How can i factor this nicely, so that i can get a form to inverse-laplace transform it

\frac{0.25s}{s^2+0.25s+0.25}

so far i get this in denominator: (s+\frac{1}{8})^2+\frac{15}{64}

after completing the square, but then the last fraction is not a square of anything.... and i need a square there, the way everything else looks...

CarlB
Oct4-05, 01:41 AM
The denominator is already a square. I don't see how you got the other stuff. The answer should be a simple polynomial multiplied by an exponential.

Carl

EvLer
Oct4-05, 02:09 AM
I don't see a square there, if (a+b)^2 = a^2+2ab+b^2

this is a simple algebra thing... i guess i'm not seeing it :frown: could you show please?

ehild
Oct4-05, 02:25 AM
How can i factor this nicely, so that i can get a form to inverse-laplace transform it

\frac{0.25s}{s^2+0.25s+0.25}

so far i get this in denominator: (s+\frac{1}{8})^2+\frac{15}{64}

after completing the square, but then the last fraction is not a square of anything.... and i need a square there, the way everything else looks...
Do not panic. 15/64 is the square of

\frac{\sqrt {15}}{8}

:smile:ehild

CarlB
Oct4-05, 02:35 AM
I don't see a square there, if (a+b)^2 = a^2+2ab+b^2

this is a simple algebra thing... i guess i'm not seeing it :frown: could you show please?

My mistake. I don't see anything wrong with the way you're doing this problem, so far.

Carl