       Re: M.U.C.

• To: mathgroup at smc.vnet.net
• Subject: [mg20622] Re: [mg20595] M.U.C.
• From: "David Park" <djmp at earthlink.net>
• Date: Thu, 4 Nov 1999 02:13:34 -0500
• Sender: owner-wri-mathgroup at wolfram.com

```CoefficientList and Thread are the routines you need to learn about.

eqn0 = E^(-2x)((-3) + 10 b - x + 6 a(1 + 5 x)) == 0;

Your equations only involve the polynomial portion on the left hand side, so we pick
that off and generate the coefficients in x:

coefflist = CoefficientList[eqn0[[1,2]], x]
{-3 + 6 a + 10 b, -1 + 30 a}

eqns = Thread[coefflist == Table[0, {Length[coefflist]}]]
{-3 + 6 a + 10 b == 0, -1 + 30 a == 0}

We can then solve the equations:

Solve[eqns]
{{a -> 1/30, b -> 7/25}}

David Park

>How can Mathematica solve the following Linear Operator for a and b?
>(E^(-2 x)((-3) + 10 b - x + 6 a(1 + 5 x)) == 0
>
>By hand it would be :
>(-3+10b+6a)=0
>(-1+30a)=0
>
>a=1/30
>b=whatever
>
>I need mathematica to group the coeeficients of x^0 and x^1, set them equal
>to 0 and solve.
>I am trying to avoid doing the gruoping by hand.  Thanks.
>
>
>
>

```