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