how would i go about the following: read in three coefficents and the constant term for three simultaneous equations in three unknowns: aix+biy+ciz=di for i=1,2,3 find the solution (for x,y and z).any help would be very much appreciated!

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- 04-14-2003nic_elmo_13simultaneous equations
how would i go about the following: read in three coefficents and the constant term for three simultaneous equations in three unknowns: aix+biy+ciz=di for i=1,2,3 find the solution (for x,y and z).any help would be very much appreciated!

- 04-14-2003Magos
use linear algebra. Put the equations in matrix form (Ax = b) and then use gauss elimination. Make sure you get no zeros in the diagonal by using pivoting.

More in-depth info:

http://www.damtp.cam.ac.uk/user/fdl/...h98/linear.htm

If time is critical, you can first split A into two triangular matrices L & R (left triangular and right triangular):

LR = A

Ax = b

LRx = b

L(Rx) = b

Rx = y

Ly= b

First, solve Ly = b, then Rx = y. Since L and R are triangular, solving them will be easier. - 04-14-2003nic_elmo_13matrices
ok thanks.i know how to do matrices by hand but how do i incorporate them into a program?i really do not understand programming!please help me!!

- 04-14-2003Magos
Since you know the dimensions:

Code:`typedef struct`

{

double _11, _12, _13;

double _21, _22, _23;

double _31, _32, _33;

}Matrix3x3;

typedef struct

{

double _1;

double _2;

double _3;

}Matrix1x3;

Matrix3x3 A;

Matrix1x3 b;

Quote:

i really do not understand programming