I’m having an issue defining the initial conditions for solving a system of differential equations
syms x Q M w(x) th(x)
%Givens
l = 10;
E = 100;
G = 40;
I = 0.1;
A = 1;
q = -1;
m = 0;
assume(0 <= x <= l);
assume(x,"real");
%Constituative Equations
Q = G*A*(diff(w,x)-th); %shear force
M = E*I*diff(th,x); %bending moment
%GDE
GDE1 = diff(M,x) + Q + m == 0;
GDE2 = diff(Q,x) + q == 0;
%BC’s (Pinned at both ends)
cond = [M(0)==0,M(l)==0,Q(0)==-q*l/2,Q(l)==-q*l/2, w(0)==0, w(l)==0];
%Set up the differential equations
eqns = [GDE1,GDE2];
[w_sol, th_sol] = dsolve(eqns, cond);
disp("w(x)=");
disp(simplify(w_sol));
disp("theta(x) =");
disp(simplify(th_sol));
I’m having difficulty defining the initial conditions to solve this system of equations. Here is the error I keep getting:
Error using mupadengine/feval_internal
Invalid initial conditions.
Error in dsolve>mupadDsolve (line 334)
T = feval_internal(symengine,’symobj::dsolve’,sys,x,options);
Error in dsolve (line 203)
sol = mupadDsolve(args, options);
Error in Problem_1 (line 36)
[w_sol, th_sol] = dsolve(eqns, cond);
Related documentationsyms x Q M w(x) th(x)
%Givens
l = 10;
E = 100;
G = 40;
I = 0.1;
A = 1;
q = -1;
m = 0;
assume(0 <= x <= l);
assume(x,"real");
%Constituative Equations
Q = G*A*(diff(w,x)-th); %shear force
M = E*I*diff(th,x); %bending moment
%GDE
GDE1 = diff(M,x) + Q + m == 0;
GDE2 = diff(Q,x) + q == 0;
%BC’s (Pinned at both ends)
cond = [M(0)==0,M(l)==0,Q(0)==-q*l/2,Q(l)==-q*l/2, w(0)==0, w(l)==0];
%Set up the differential equations
eqns = [GDE1,GDE2];
[w_sol, th_sol] = dsolve(eqns, cond);
disp("w(x)=");
disp(simplify(w_sol));
disp("theta(x) =");
disp(simplify(th_sol));
I’m having difficulty defining the initial conditions to solve this system of equations. Here is the error I keep getting:
Error using mupadengine/feval_internal
Invalid initial conditions.
Error in dsolve>mupadDsolve (line 334)
T = feval_internal(symengine,’symobj::dsolve’,sys,x,options);
Error in dsolve (line 203)
sol = mupadDsolve(args, options);
Error in Problem_1 (line 36)
[w_sol, th_sol] = dsolve(eqns, cond);
Related documentation syms x Q M w(x) th(x)
%Givens
l = 10;
E = 100;
G = 40;
I = 0.1;
A = 1;
q = -1;
m = 0;
assume(0 <= x <= l);
assume(x,"real");
%Constituative Equations
Q = G*A*(diff(w,x)-th); %shear force
M = E*I*diff(th,x); %bending moment
%GDE
GDE1 = diff(M,x) + Q + m == 0;
GDE2 = diff(Q,x) + q == 0;
%BC’s (Pinned at both ends)
cond = [M(0)==0,M(l)==0,Q(0)==-q*l/2,Q(l)==-q*l/2, w(0)==0, w(l)==0];
%Set up the differential equations
eqns = [GDE1,GDE2];
[w_sol, th_sol] = dsolve(eqns, cond);
disp("w(x)=");
disp(simplify(w_sol));
disp("theta(x) =");
disp(simplify(th_sol));
I’m having difficulty defining the initial conditions to solve this system of equations. Here is the error I keep getting:
Error using mupadengine/feval_internal
Invalid initial conditions.
Error in dsolve>mupadDsolve (line 334)
T = feval_internal(symengine,’symobj::dsolve’,sys,x,options);
Error in dsolve (line 203)
sol = mupadDsolve(args, options);
Error in Problem_1 (line 36)
[w_sol, th_sol] = dsolve(eqns, cond);
Related documentation dsolve, differential equations, initial conditions, system of equations, invalid initial conditions, mupadengine error, feval_internal error MATLAB Answers — New Questions