The following basic math functions are available in Texis:
acos, asin, atan, atan2, ceil, cos,
cosh, exp, fabs, floor, fmod,
log, log10, pow, sin, sinh, sqrt,
tan, tanh.
All of the above functions call the ANSI C math library function
of the same name, and return a result of type double.
pow, atan2 and fmod take two double arguments,
the remainder take one double argument. Added in version:
2.6.931790000
In addition, the following math-related functions are available:
isNaN(x)
Returns 1 if x is a float or double NaN (Not a Number) value,
0 if not. This function should be used to test for NaN, rather than
using the equality operator (e.g. x = 'NaN'), because the
IEEE standard defines NaN == NaN to be false, not true as
might be expected. Added in version 5.01.1193955406 20071101.