# How to plot the graph?

GROUPS:
 DSolve[{Derivative[2][Subscript[u, 00]][y] +       Rey*S*Derivative[1][Subscript[u, 00]][y] == -Rey*      Gr*((E^(Pr Rey S - Pr Rey S y) (-1 + E^(Pr Rey S y)))/(-1 + E^(        Pr Re S))),     Subscript[u, 00][0] == h*Derivative[1][Subscript[u, 00]][0],     Subscript[u, 00][1] == 1}, Subscript[u, 00][y], y] // FullSimplify  {{Subscript[u, 0][     y] -> (E^(-Rey S (Pr (-1 + y) + y)) (-E^(Rey S y) Gr -         E^(S (Rey + Pr (Re + Rey (-1 + y)))) (-1 + Pr) Pr Rey S^2 +         E^(Rey S (1 + y)) Gr (1 + h Rey S) +         E^(S (Pr Re + Rey + Pr Rey (-1 + y) + Rey y)) (-1 +            Pr) Pr Rey S^2 (1 + h Rey S) -         E^(Rey S (1 + Pr y)) Gr (1 + Pr (-1 + Pr + h Pr) Rey S) +         E^(Rey S (1 + Pr (-1 + y))) (Gr + (-1 + Pr) Pr Rey S^2) -         E^(Rey S (1 + Pr (-1 + y) + y)) (1 +            h Rey S) (Gr + (-1 + Pr) Pr Rey S^2) -         E^(Rey S (1 + y + Pr y))          Gr (-1 + Pr) Pr Rey S (1 + h Rey S) (-1 + y) +         E^((1 + Pr) Rey S y)          Gr (1 + Pr Rey S (h Pr + (-1 + Pr) y))))/((-1 + E^(        Pr Re S)) (-1 + Pr) Pr Rey S^2 (-1 +         E^(Rey S) (1 + h Rey S)))}}Plot[Subscript[u, 00][y], {y, 0, 1}]When I try to plot this u00, the plot was empty. why?
4 years ago
6 Replies
 Hello, please post copyable code! Take a few minutes to read this tutorial about correct posting – especially of Mathematica code:How to type up a post: editor tutorial & general tipsIf you will not follow the tutorial, other members of community may not be able to test your code. To edit your post – click “Edit” in the lower right corner of your post.
4 years ago
 There appears to be several possible reasons:What I take to be variables Rey, S, Gr, S, Pr and h do not appear to have any values associated wtih them, thus they are purely abstract symbols. Plot ultimately has to have either closed form formulas with numbers to work with or Interpolation type functions to work with.The rule that DSolve has come up with refers to u subscript 0, not u subscript 00 as in the equations in DSolve. Did you somehow delete a zero?There hasn't been anything set to equal the replace part rule, thus it could not yet have been used in Plot even if it had been employed.I find that it's always best to strip away the outer brackets from rules, and I don't see that that has yet been done.The rule hasn't been employed in Plot, thus u subscript 00 is still an empty symbol.In summary, unless those symbols have some inherent meaning I don't understand, you are still several steps away from being able to Plot because the whole thing is still too abstract.
4 years ago
 I had changed Subscript[u,00] to Subscript[u,0]. Eventhough the plot was still empty.