In[]:=
Clear[x];​​l=0.5;​​F=13000/4;​​f=0.12;​​Eel=200000000000;​​Iin=0.05*(4*0.008)^3/4;​​k[x_]=(2f/l)/(1+4(x/l)^2(f/l)^2)^(3/2);​​dsdx[x_]=Sqrt[(1+4(x/l)^2(f/l)^2)];​​M[x_]=-Fx-Fl/2;​​θ[x_]=((u'[x]/dsdx[x])'-(k'[x]u'[x])/(dsdx[x]k[x]))/k[x]+k[x]u[x];​​NDSolve[{M[x]-EelIinθ'[x]==0,u[-l/2]==0,u'[-l/2]==0},u[x],{x,-0.5,0.5}]
NDSolve
:The derivative operator Derivative[1] in
′
′
u
[x]
1+0.9216
2
x
should act on the pure function.
Out[]=
NDSolve-812.5-3250x-81920.-
1.3271xu[x]
5/2
(1+0.9216
2
x
)
+
0.48
′
u
[x]
3/2
(1+0.9216
2
x
)
+5.76x
1+0.9216
2
x
′
′
u
[x]
1+0.9216
2
x
+
2.7648x
′
u
[x]
3/2
(1+0.9216
2
x
)
+2.08333
3/2
(1+0.9216
2
x
)
′
-
0.9216x
′
u
[x]
3/2
(1+0.9216
2
x
)
+
′′
u
[x]
1+0.9216
2
x
-
7.64412
2
x
′
u
[x]
5/2
(1+0.9216
2
x
)
+
2.7648
′
u
[x]
3/2
(1+0.9216
2
x
)
+
2.7648x
′′
u
[x]
3/2
(1+0.9216
2
x
)
0,u[-0.25]0,
′
u
[-0.25]0,u[x],{x,-0.5,0.5}