Re: Equation question

Am 21.09.2006 06:09 schrieb Herb:
a + b = 90
b + c = 130
c + d = 90
d + e = 95
e + f = 90
f + a = 45

How can I find the value of " e " ?
Thanks for any help !!

Write it in a matrix scheme:

| a |
| b |
| c |
| d |
| e |
| f |
--------
1 1 0 0 0 0 | 90 |
0 1 1 0 0 0 |130 |
0 0 1 1 0 0 | 90 |
0 0 0 1 1 0 | 95 |
0 0 0 0 1 1 | 90 |
1 0 0 0 0 1 | 45 |


denote the lhs-matrix as A, the [a,b,c...] matrix as X
and the rhs-matrix []90,130,...] as Y.

Then

A * X = Y
X = inv(A)*Y

So you just invert A, leftmultiply with Y and
get the result.

Gottfried Helms
.

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