Question

How to calculate the determinant of a 3X3 matrix in JavaScript

Answer 1

const arr = [ [ 6, 1, 1 ], [ 4, -2, 5 ], [ 2, 8, 7 ] ]
  
/* 
 *       a b c
 * arr = d e f
 *       g h i
 * 
 * determinant = a*(e*i - f*h) - b*(d*i-f*g) + c*(d*h - e*g)
 * 
 */
  
const determinant = arr[0][0] * (arr[1][1]*arr[2][2] - arr[1][2]*arr[2][1]) -
                    arr[0][1] * (arr[1][0]*arr[2][2] - arr[1][2]*arr[2][0]) +
                    arr[0][2] * (arr[1][0]*arr[2][1] - arr[1][1]*arr[2][0]);
  
 
console.log(determinant);



 
/*
run:
   
-306 
     
*/

 

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