    @Test
    @DisplayName("Test P22")
    public void testP22() {

        final double increment = 1e-4;
        final AssociatedLegendrePolynomial alp = new AssociatedLegendrePolynomial(2,2);
        for (double x = -1.0;x<=1.0;x+=increment) {
            assertEquals(3.0*(1-Math.pow(x,2)), alp.value(x), 1e-8);
        }
    }