public function testAdditivityInTheScalarForScalarMultiplication(array $A)
{
$A = new Vector($A);
$c = 2;
$d = 9;
$⟮c+d⟯A = $A->scalarMultiply($c + $d);
$⟮cA+dA⟯ = $A->scalarMultiply($c)->add($A->scalarMultiply($d));
$this->assertEquals($⟮c+d⟯A, $⟮cA+dA⟯);
$this->assertEquals($⟮c+d⟯A->getVector(), $⟮cA+dA⟯->getVector());
}