# Thread: simplify expression into form of s^2 +A*s +B

1. ## simplify expression into form of s^2 +A*s +B

Should be easy for me, but it is not! Could someone show the steps to put the following statement into form of s^2 +As +B?
s/(Rc*C) +s^2 +s/(C(L*s+RL))

2. ## Re: simplify expression into form of s^2 +A*s +B

Originally Posted by ncbill
Should be easy for me, but it is not! Could someone show the steps to put the following statement into form of s^2 +As +B?
s/(Rc*C) +s^2 +s/(C(L*s+RL))
You already have the " $s^2$" so you just need to add s/(Rc*C)+ s/(L*s+ RL)= (1/(Rc*C)+ 1/(L*s+ RL). Add the fractions. There will be NO "+ B" part.

3. ## Re: simplify expression into form of s^2 +A*s +B

Hello, ncbill!

Your notation is confusing.
Please restate the problem clearly.

Could someone show the steps to put the following statement into form of s^2 +As +B?
. . s/(Rc*C) +s^2 +s/(C(L*s+RL))

You seem to use "*" for multiplication.

Then what does "Rc" mean?
. . Is that a subscript?. $R_c$
Does "RL" mean $R_L\,?$

You seem to have: . $\frac{s}{CR_c} + s^2 + \frac{s}{C(Ls + R_L)}$

Note that there is an $s$ in the denominator.
. . We can never get it into the form $s^2 + As + B.$

4. ## Re: simplify expression into form of s^2 +A*s +B

I totally agree with Soroban, there does not seem to be any chance. could be you have posted the question wrong. Please have a re-look.

5. ## Re: simplify expression into form of s^2 +A*s +B

Wow! You folks are incredible. Thanks Soroban, your interpretation of my primitive notation is correct. I do not yet have the tools to typeset it so beautifully, not to mention that I lack the experience. You have validated my frustration in trying to force the expression into that quadratic form.
Now for an interesting twist...
Can it be done if "s" is a complex number?