How find symbolic solution matlab
조회 수: 4 (최근 30일)
이전 댓글 표시
I am trying to solve this simple autonomous differential equation using the dsolve function but MATLAB cannot find a symbolic solution to the function. Does anyone have any idea how I could solve the problem? The code is the following:
clc, clear all
syms y(t)
eqn = diff(y,t,2) == -9.8*sin(y) - 0.5*y'
Dy = diff(y,t)
cond = [y(0)==0.8, Dy(0)==0.8]
ySol(t) = dsolve(eqn,cond)
Thanks in advance to anyone who can help me.
댓글 수: 4
John D'Errico
2020년 11월 23일
It cannot find a symbolic solution because one apparently does not exist. And that is why Stephan was asking if you really intended sin(t), not sin(y), as there may well be a solution in that case.
답변 (1개)
Stephan
2020년 11월 23일
It appears that there either is no symbolic solution or Matlab is not powerful enough to find one. For sin(t) it would work. However Wolfram Alpha also does not provide an analytical solution for this ode - here is the numeric approach:
syms y(t)
Dy = diff(y,t)
eqn = diff(y,t,2) == -9.8*sin(y) - 0.5*Dy
% make numeric function from symbolic
[V,S] = odeToVectorField(eqn)
fun = matlabFunction(V,'Vars',{'t','Y'})
% solve ode numeric
[t,y] = ode45(fun,[0 10],[0.8, 0.8]);
plot(t,y)
참고 항목
카테고리
Help Center 및 File Exchange에서 Symbolic Math Toolbox에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!