public void testTan() {
        System.out.println("testTan");
        Generic_BigDecimal a_Generic_BigDecimal = new Generic_BigDecimal(1000);
        BigDecimal x;
        int decimalPlaces;
        RoundingMode roundingMode;
        BigDecimal expResult = null;
        BigDecimal result = null;
        BigDecimal aPI1000 = a_Generic_BigDecimal.get_PI();
        decimalPlaces = 100;
        roundingMode = RoundingMode.HALF_UP;
        // Test PI/4
        x = Generic_BigDecimal.divideRoundIfNecessary(
                aPI1000,
                BigInteger.valueOf(4),
                decimalPlaces + 2,
                roundingMode);
        expResult = new BigDecimal("1");
        expResult.setScale(decimalPlaces);
        result = Generic_BigDecimal.tan(
                x,
                a_Generic_BigDecimal,
                decimalPlaces,
                roundingMode);
        result = result.stripTrailingZeros();
        assertEquals(expResult, result);
        roundingMode = RoundingMode.HALF_UP;
    }