asin
====

.. qcs:function:: asin(x)
    :category: math

    :param x: series or numeric value 
    :type x:  :qcs:type:`series` or :qcs:type:`numeric`
    :returns: same type as **x**

    Returns the arcsine in radians in the range 
    :math:`[-\frac{\pi}{2},\frac{\pi}{2}]` of a number in the 
    range :math:`[-1,1]`, **nil** otherwise