[ Closed ] I need related gamma function

The gamma function is implemented as gamma(x). The incomplete gamma functions are not directly supported, but in the beta version of Graph 4.4, which has better support for numeric integration you can create them as custom functions:

u_gamma(s,x)=integrate(t^(s-1)*e^-t, t, x, inf)
l_gamma(s,x)=integrate(t^(s-1)*e^-t, t, 0, x)

The Riemann zeta function is implemented as zeta(x), but the Hurwitz zeta function is not implemented in Graph. I think it will be possible to plot it in Graph 4.4 when it gets finished, but currently the best Graph can do is the sum function, which does not support infinity as its limits.