The functions in gnuplot are the same as the corresponding functions in the Unix math library, except that all functions accept integer, real, and complex arguments, unless otherwise noted.
For those functions that accept or return angles that may be given in either degrees or radians (sin(x), cos(x), tan(x), asin(x), acos(x), atan(x), atan2(x) and arg(z)), the unit may be selected by set angles, which defaults to radians.
abs
acos
acosh
arg
asin
asinh
atan
atan2
atanh
besj0
besj1
besy0
besy1
ceil
cos
cosh
erf
erfc
exp
floor
gamma
ibeta
inverf
igamma
imag
invnorm
int
lgamma
log
log10
norm
rand
real
sgn
sin
sinh
sqrt
tan
tanh
column
tm_hour
tm_mday
tm_min
tm_mon
tm_sec
tm_wday
tm_yday
tm_year
valid