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Cramer's rule: Difference between revisions

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Cramer's rule (view source)

Revision as of 14:51, 23 February 2023

451 bytes added ,  1 year ago
→‎{{header|Racket}}
Line 2,311:
 
=={{header|Racket}}==
<syntaxhighlight lang="racket">#lang typed/racket▼
#lang racket
(require math/matrix)
 
(define sys
{{incorrect|Racket|Doesn't really use Cramer's rule}}
(matrix [[2 -1 5 1]
[3 2 2 -6]▼
[1 3 3 -321]▼
[5 -2 -3 3]]))▼
 
(define soln
▲<syntaxhighlight lang="racket">#lang typed/racket
(require math/ (col-matrix [-3 -32 -47 49]))
 
(define (matrix-set-column M new-col idx)
(matrix-augment (list-set (matrix-cols M) idx new-col)))
 
(define A (matrix [[2 cramers-1 5rule M 1]soln)
(let ([denom (matrix-determinant M)]
▲ [3 2 2 -6]
[1nvars (matrix-num-cols 3 3 -1M)])
(letrec ([roots (λ (position)
▲ [5 -2 -3 3]]))
(if (>= 49])position nvars)▼
-47 '()▼
(cons (/ (matrix-determinant
(matrix-set-column M soln position))
denom)
(roots (add1 position)))))])
(map cons '(w x y z) (roots 0)))))
 
(cramers-rule sys soln)
(define B (col-matrix [ -3
</syntaxhighlight>
▲ -32
▲ -47
▲ 49]))
 
(matrix->vector (matrix-solve A B))</syntaxhighlight>
{{out}}
 
<pre>'#((w . 2) (x . -12) (y . -4) (z . 1))</pre>
 
=={{header|Raku}}==
Dr-neptune
8

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