Plot[f, {x, $x_{min}$, $x_{max}$}]Plot[{$f_1$, $f_2$, ...}, {x, $x_{min}$, $x_{max}$}]Plot[{Sin[x], Cos[x], x / 3}, {x, -Pi, Pi}]
Plot[Sin[x], {x, 0, 4 Pi}, PlotRange->{{0, 4 Pi}, {0, 1.5}}]
Plot[Tan[x], {x, -6, 6}, Mesh->Full]
Plot[x^2, {x, -1, 1}, MaxRecursion->5, Mesh->All]
Plot[Log[x], {x, 0, 5}, MaxRecursion->0]
Plot[Tan[x], {x, 0, 6}, Mesh->All, PlotRange->{{-1, 5}, {0, 15}}, MaxRecursion->10]
A constant function:
Plot[3, {x, 0, 1}]