Try to learn something about everything, and everything about somethingThomas Huxley “Darwin's bulldog” (1824-1895)

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public:calculator:guides:dm32_simultaneos_equations [17/04/26 18:11 BST] – created johnpublic:calculator:guides:dm32_simultaneos_equations [18/04/26 06:53 BST] (current) – [Use] john
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 ** From the Owners Manual ** ** From the Owners Manual **
  
-===== Section One =====+===== Statefile =====
  
 +Provided by Swiss Micros [[https://technical.swissmicros.com/dm32/examples/STATE/SIMEQ.d32]]
  
-===== Section Two =====+Local copy {{ :public:calculator:guides:simeq.d32 |}} 
 + 
 + 
 +===== Overview ===== 
 + 
 +This set of programs allows the solution of 3x3 and 2x2 systems of equations, as well as the inverse and determinate of the matrix representing the coefficients. 
 + 
 +The set of equations is represented by a 3 x 4 array of numbers, with the first 3 columns representing the coefficients of the equations and the 4th column the "value" of the equations. 
 + 
 +For example 
 + 
 +'' Ax + Dy + Gz = J '' 
 + 
 +'' Bx + Ey + Hz = K '' 
 + 
 +'' Cx + Fy + Iz = L '' 
 + 
 +These equations can be represented in matrix form 
 + 
 +'' 
 +| A D G | | x |   | J | 
 +| B E H | | y | = | K | 
 +| C F I | | z |   | L | 
 + 
 +'' 
 + 
 + 
 +This is effectively 
 + 
 +'' A x X = B '' 
 + 
 +and therefore  
 + 
 +'' X = B / A '' 
 + 
 +or  
 + 
 +''X = B x A<sup>-1</sup> '' 
 + 
 +The unknown matrix is obtained by multiplying ''B'' by the ''inverse of A'' 
 + 
 +They are entered sequentially in the order  
 + 
 +''ABCDEFGHIJKL'' 
 + 
 +===== Use ===== 
 + 
 +Enter the values of the 3x3 matrix and the 3x1 column vector by using prog. A 
 + 
 +  * <key>XEQ</key> <key>'A'</key> 
 +  * Enter each value at the prompt followed by <key>R/S</key> 
 +  * Once all values ''A'' -> ''L'' are entered you can  
 +    * find the determinant of the coefficient matrix with prog ''D'' 
 +      * this is not required for a simple solution, but might be useful for other purposes? 
 +    * **I**nvert the coefficient matrix A with prog. ''I'' 
 +      * <key>XEQ</key> <key>'I'</key> 
 +    * **M**ultiply the column vector by this inverse matrix using prog. ''M'' 
 +      * <key>XEQ</key> <key>'M'</key> 
 +      * This gives the resulting ''X'', ''Y'' and ''Z'' by pressing <key>R/S</key> to step through them 
 + 
 +===== Examples ===== 
 + 
 +==== 3 x 3 ==== 
 + 
 +A system of equations with 3 unknowns ''x'', ''y'' and ''z'' 
 + 
 + 
 +''23x + 15y + 17z = 31'' 
 + 
 +'' 8x + 11y -  6z = 17'' 
 + 
 +'' 4x + 15y + 12z = 14'' 
 + 
 +<note> 
 + 
 +Beware! 
 + 
 +You enter each value in sequence going **down the columns** in sequence 
 + 
 +Which is the opposite sense to the way matrices are entered in DM15L and DM41X  
 + 
 +</note> 
 + 
 +  * <key>XEQ</key> <key>'A'</key> 
 +    * 23 <key>R/S</key> 
 +    * 8 <key>R/S</key> 
 +    * 4 <key>R/S</key> 
 +    * 15 <key>R/S</key> 
 +    * 11 <key>R/S</key> 
 +    * 15 <key>R/S</key> 
 +    * 17 <key>R/S</key> 
 +    * 6 <key>'+/-'</key> <key>R/S</key> 
 +    * 12 <key>R/S</key> 
 +    * 31 <key>R/S</key> 
 +    * 17 <key>R/S</key> 
 +    * 14 <key>R/S</key> 
 +  * Find the inverse <key>XEQ</key> <key>'I'</key> 
 +  * Multiply <key>XEQ</key> <key>'M'</key> 
 +  * Display shows solutions 
 +    * ''X = 0.930622'' <key>R/S</key> 
 +    * ''Y = 0.794258'' <key>R/S</key> 
 +    * ''Z = -0.136364'' 
 +  * You can inspect the inverted matrix by running ''A'' again 
 +    * <key>XEQ</key> <key>'A'</key>  
 +    * ''A ? 0.048'' <key>R/S</key> 
 +    * ''B ? -0.026'' <key>R/S</key> 
 +    * etc....etc... 
 +  * You can re-invert A back to the original state by running prog ''I'' again 
 +  * You can see the determinant of A by running prog ''D'' 
 + 
 +==== 2x2 ==== 
 + 
 +The programs expect a 3x3 matrix. If the system is 2x2 you have to use dummy values to pad out to 3x3 
 + 
 +Set ''C, F, H, G, L = 0'' and ''I = 1'' 
 + 
 +e.g. 
 + 
 +'' 2x + 3y = 6 '' 
 + 
 +'' 8x - 4y = 9 '' 
 + 
 +This becomes 
 + 
 +'' 2x + 3y + 0z = 6 '' 
 + 
 +'' 8x - 4y + 0z = 9 '' 
 + 
 +'' 0x + 0y + 1z = 0 '' 
 + 
 +and is entered 
 + 
 +  * <key>XEQ</key> <key>'A'</key> 
 +    * 2 <key>R/S</key> 
 +    * 8 <key>R/S</key> 
 +    * 0 <key>R/S</key> 
 +    * 3 <key>R/S</key> 
 +    * 4 <key>'+/-'</key> <key>R/S</key> 
 +    * 0 <key>R/S</key> 
 +    * 0 <key>R/S</key> 
 +    * 0 <key>R/S</key> 
 +    * 1 <key>R/S</key> 
 +    * 6 <key>R/S</key> 
 +    * 9 <key>R/S</key> 
 +    * 0 <key>R/S</key> 
 +  * Find the inverse <key>XEQ</key> <key>'I'</key> 
 +  * Multiply <key>XEQ</key> <key>'M'</key> to find the unknowns 
 +    * ''X = 1.59375'' <key>R/S</key> 
 +    * ''Y = 0.93750'' <key>R/S</key> 
 +    * ''Z = 0.00000'' <key>'C'</key>
  
  
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-{{tag>}}+{{tag>calculator dm32}}
  
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