Help me for solve the Eq Error in IBC

Questions
,
1

DSolve[{Et’‘’'[x] + Dt’‘ - vt’[x] == kt, t’[0] = 0,
t’[L] = 0, t’‘[0] = 0, t’'[L] = 0
}, t, x]

Untitled-1.nb (8.66 KB)

2

Mathematica is case sensitive and built-in symbols are always capitalized.
Don’t use capital D for your own symbol by the way.
With corrected syntax:

 DSolve[{e*t''''[x] + d*t''[x] - v*t'[x] == k*t[x], t'[0] == 0, t'[L] == 0, t''[0] == 0, t''[L] == 0}, t[x], x]

 (* {{t[x] -> 0}}  *)

Gives only a trivial solution.

Regards M.I.