Re: Why not expected result for Inverse[] ?
- To: mathgroup at smc.vnet.net
- Subject: [mg40535] Re: [mg40533] Why not expected result for Inverse[] ?
- From: Dr Bob <majort at cox-internet.com>
- Date: Wed, 9 Apr 2003 20:26:07 -0400 (EDT)
- References: <200304090534.BAA08406@smc.vnet.net>
- Reply-to: majort at cox-internet.com
- Sender: owner-wri-mathgroup at wolfram.com
You haven't told us what you actually did, so how can we tell you what you
did wrong?
Did you, for instance, enter something like this?
z=[k]-w^2*m
I hope not! But that's what you SAID you did. (Speak to us in Mathematica
notation.)
Copy and paste what you actually did into e-mail including the definitions
of k, m, and z and the invocation of Inverse, and we should be able to
straighten it out. Meanwhile, here's a right way to do it. Not THE right
way, but one right way.
m = {{a, b}, {c, d}};
k = {{e, f}, {g, h}};
z = k - w^2 m;
Inverse[z]
{{(h - d*w^2)/((-f)*g + e*h - d*e*w^2 + c*f*w^2 + b*g*w^2 - a*h*w^2 -
b*c*w^4 + a*d*w^4), (-f + b*w^2)/((-f)*g + e*h - d*e*w^2 + c*f*w^2 +
b*g*w^2 - a*h*w^2 - b*c*w^4 + a*d*w^4)}, {(-g + c*w^2)/((-f)*g + e*h -
d*e*w^2 + c*f*w^2 + b*g*w^2 - a*h*w^2 - b*c*w^4 + a*d*w^4), (e - a*w^2)/((-
f)*g + e*h - d*e*w^2 + c*f*w^2 + b*g*w^2 - a*h*w^2 - b*c*w^4 + a*d*w^4)}}
Bobby
On Wed, 9 Apr 2003 01:34:12 -0400 (EDT), <twm145 at psu.edu> wrote:
> I define two 2X2 square matrices, m & k
> Then define a z matrix, [k]-w^2*[m]
>
> Why does Inverse[z], not give inverse, just gives output as Inverse[z]
>
> instead I have to use Inverse[%]
>
> Does'nt make sense to me. Help me understand please.
>
> Tom
>
>
--
majort at cox-internet.com
Bobby R. Treat
- References:
- Why not expected result for Inverse[] ?
- From: twm145@psu.edu
- Why not expected result for Inverse[] ?