ParametricPlot3D[{2 cos [u], 2 sin [u], v}, {u, 0, 2 [Pi]}, {v, 0, 6}] I try to plot and only appear the space but no the graphic, help me!
Build in functions always start with capital letters (they also turn black when you type them) try this:
ParametricPlot3D[{2 Cos[u], 2 Sin[u], v}, {u, 0, 2 Pi}, {v, 0, 6}]
Mathematica if fiercely case sensitive.
Replace cos with Cos and sin with Sin