Matlab error with differential equations and syms - matlab

Question

I have 2 differential equations that are related to each other by their B.C.
I try to solve them with the following code:
syms v1(x) v2(x) L;
E = 1; %Modulous young
I = 1; %Moment of inertia
P = 1; %Force
Differintial_Equation1 = E*I*diff(v1,x,2) == -(sqrt(2)/2)*P*x;
Differintial_Equation2 = E*I*diff(v2,x,2) == -(sqrt(2)/2)*P*(L-x);
eqs = [Differintial_Equation1, Differintial_Equation2];
Dv1 = diff(v1,x); %v1'
Dv2 = diff(v2,x); %v2'
cond1 = [v1(0)==0, v1(L)+L*cos(pi/4) == v2(0)-L*cos(pi/4)]; %B.C
cond2 = [v2(L)==0, Dv1(L)+(pi/4) == Dv2(0)-(pi/4)]; %B.C 2
conds = [cond1, cond2];
vSol(x) = dsolve(eqs, conds);
I am getting an error:
Error using sym/subsindex (line 766)
Invalid indexing or function definition. When defining a function, ensure
that the arguments are
symbolic variables and the body of the function is a SYM expression. When
indexing, the input must be
numeric, logical, or ':'.
Error in sol_2nd (line 29)
vSol(x) = dsolve(eqs, conds);
If I remove the B.C on Dv and change it to v it works fine, what am I missing here?
Thanks in advance.

Answer 1

In your code dsolvereturns a structure containing the solutions.
You can use [v1sol(x) v2sol(x)]= dsolve(eqs, conds);
So we have this:
syms v1(x) v2(x) L;
E = 1; %Modulous young
I = 1; %Moment of inertia
P = 1; %Force
Differintial_Equation1 = E*I*diff(v1,x,2) == -(sqrt(2)/2)*P*x;
Differintial_Equation2 = E*I*diff(v2,x,2) == -(sqrt(2)/2)*P*(L-x);
eqs = [Differintial_Equation1, Differintial_Equation2];
Dv1 = diff(v1,x); %v1'
Dv2 = diff(v2,x); %v2'
cond1 = [v1(0)==0, v1(L)+L*cos(pi/4) == v2(0)-L*cos(pi/4)]; %B.C
cond2 = [v2(L)==0, Dv1(L)+(pi/4) == Dv2(0)-(pi/4)]; %B.C 2
conds = [cond1, cond2];
[v1sol(x) v2sol(x)]= dsolve(eqs, conds);