When fitting data to a model, it is often important to obtain additional results to compare the data to the fitted function. You may wish to check the significance of ...
Conjugate[z] or z\[Conjugate] gives the complex conjugate of the complex number z.
ContourPlot3D[f, {x, x_min, x_max}, {y, y_min, y_max}, {z, z_min, z_max}] produces a three-dimensional contour plot of f as a function of x, y, and z. ContourPlot3D[f == g, ...
ExpIntegralEi[z] gives the exponential integral function Ei(z).
FresnelS[z] gives the Fresnel integral S(z).
InverseEllipticNomeQ[q] gives the parameter m corresponding to the nome q in an elliptic function.
JacobiCD[u, m] gives the Jacobi elliptic function cd(u | m).
JacobiDC[u, m] gives the Jacobi elliptic function dc(u | m).
JacobiSC[u, m] gives the Jacobi elliptic function sc(u | m).
LogGamma[z] gives the logarithm of the gamma function log \[CapitalGamma](z).