# MATLAB: ODE symbolic Boundary conditions in respect to another variable

bcboundary conditiondsolveMATLABsymbolic

Hello,
I have an ODE with three boundary conditions to solve (see code bellow). Having run this code as a .mlx file I see that cond2 is read as: it takes the derivative in respects to a not r. I wanted to produce such a limit: I tried changing the condition to:
``cond2 = Dw(r==a) == 0``
or
``cond2 = Dw(r=a) == 0``
but it did not do the trick. Could you please tell me how to properly input the boudary condition in respect to r?
Thank you,
Bellow is my code:
``clear; clc;syms a P G t nu F Q r D w(r) h% ForcesF = - pi * a^2 * P;Q = (pi*r^2*P) / (2*pi*r);% ODEode = diff(((1/r)*diff((r*diff(w,r)),r)),r) == Q/D;Dw = diff(w,r);cond1 = Dw(0) == 0;cond2 = Dw(a) == 0cond3 =  w(a) == 0;conds = [cond1 cond2 cond3];wSol(r) = dsolve(ode,conds);w_0 = subs(wSol,r,0);``

``syms x(t) aDx = diff(x);eq = diff(x, t, 2) == x;cond = [x(0)==1; Dx(a)==0];sol = dsolve(eq, cond);fplot(subs(sol, a, 1), [0 2]) `` 