static double[][] cofactor(double[][] A){
		double[][] B = new double[A.length][A.length];
		for(int i = 0; i < A.length; i++){
			for(int j = 0; j < A.length; j++){
				B[i][j] = Math.pow(-1,i+j)*det(minor(A,i,j));
			}
		}
		return B;
	}