# Beginner needs help

Posted 9 years ago
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 This is giving me a logical value for my boundary condition equations.  It's not solving my equations.  Where did I go wrong? Attachments:
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Posted 9 years ago
 it can read..., z, {x,1,1},{y,1,1}]not much space left. Take an unit square instead for the independent variables.One gets explanations for the messages in the help ref/message/NDSolve/deqn, so a derivative on the boundary is not specified byD[z[x,0],y]==0because that gives True (z[x,0] does not depend on y), but using(D[z[x,y],y]/.y->0)==0if done so one hasIn[108]:= NDSolveValue[{D[z[x, y], {x, 4}] +     2 D[z[x, y], {x, 2}, {y, 2}] + D[z[x, y], {y, 4}] == q/d,  z[x, 0] == 0,   z[0, y] == 0, (D[z[x, y], y] /. y -> 0) ==    0, (D[z[x, y], x] /. x -> 0) == 0 }, z, {x, 0, 1}, {y, 0, 1}]During evaluation of In[108]:= NDSolveValue::ivone: Boundary values may only be specified for one independent variable. Initial values may only be specified at one value of the other independent variable. >>now one reads ref/message/NDSolve/ivone and considers the type of the equation, especially it statesThe partial differential equation solver used by NDSolve is designed to solve initial value problems.purely elliptic problems are not in the scope of NDSolve[], if I understand it right.
Posted 9 years ago
 Udo, thanks for taking the time to help me.  That means a lot to me.  I'll just code these equations in a general purpose programming language.  Bob.