# Matlab Question Help

• Sep 20th 2009, 06:37 PM
xpack
Matlab Question Help
http://img30.imageshack.us/img30/9937/74000118.png

Need help with this problem, I can understand how exactly to work it, could someone help?
• Sep 20th 2009, 06:45 PM
CaptainBlack
Quote:

Originally Posted by xpack
http://img30.imageshack.us/img30/9937/74000118.png

Need help with this problem, I can understand how exactly to work it, could someone help?

The first thing to do is write those equations out in an orderly fashion as a set of linear equations in the F's and convert that into matrix form. Have you done that? What do you get?

CB
• Sep 20th 2009, 06:55 PM
xpack
You mean like finding
f1=
f2=
... and so on?
• Sep 20th 2009, 08:20 PM
CaptainBlack
Quote:

Originally Posted by xpack
You mean like finding
f1=
f2=
... and so on?

No I mean:

http://www.sitmo.com/gg/latex/latex2...%0A\end{array}

Now rewrite this as a matrix equation.

CB
• Sep 20th 2009, 08:24 PM
elbarto
Write it out so its in the form $Ax = b$.

$A$ will be a 9x9 matrix. The first row might occurding to your first equation would be

$\left[ \begin{matrix}
\frac{1}{\sqrt{2}} & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \end{matrix} \right]$

Captain Black has beat me to it so I will not go any further (I am still very slow with Latex) (Nod)

Regards Elbarto
• Sep 20th 2009, 08:49 PM
xpack
Okay i got the matrix equation

A= [ cosd(45),1,0,0,0,0,0,0,0; -cosd(45),0,0,1,cosd(48.81),0,0,0,0; -sind(45),0,-1,0,-sind(48.81),0,0,0,0; 0,0,0,-1,0,0,0,cosd(48.81),0; 0,0,0,0,0,0,-1,-sind(48.81),0; 0,0,0,0,-cosd(48.81),1,0,0,1; 0,0,0,0,sind(48.81),0,1,0,0; 0,0,0,0,0,0,0,sind(48.81),0; 0,0,0,0,0,0,0,-cosd(48.81),-1 ]

Now where do I go from here?
• Sep 20th 2009, 09:57 PM
CaptainBlack
Quote:

Originally Posted by xpack
Okay i got the matrix equation

A= [ cosd(45),1,0,0,0,0,0,0,0; -cosd(45),0,0,1,cosd(48.81),0,0,0,0; -sind(45),0,-1,0,-sind(48.81),0,0,0,0; 0,0,0,-1,0,0,0,cosd(48.81),0; 0,0,0,0,0,0,-1,-sind(48.81),0; 0,0,0,0,-cosd(48.81),1,0,0,1; 0,0,0,0,sind(48.81),0,1,0,0; 0,0,0,0,0,0,0,sind(48.81),0; 0,0,0,0,0,0,0,-cosd(48.81),-1 ]

Now where do I go from here?

F=A\[0,0,1000,0,500,0,4000,-1105.14,0]'

should do it.

CB