matlab微分方程组求解symsa,b,c,d;dsolve('Dy(1)=1/2*a*y(2)*j','Dy(2)=-(c+d)*y(2)*j+1/2*a*y(1)*j+1/2*b*y(3)*j','Dy(3)=-d*y(3)*j+1/2*b*y(2)*j')error('symbolic:dsolve:errmsg2','TherearemoreODEsthanvariables.')为什么错啦,哪里有问题,

Question

matlab微分方程组求解
syms a,b,c,d;
dsolve('Dy(1)=1/2*a*y(2)*j','Dy(2)=-(c+d)*y(2)*j+1/2*a*y(1)*j+1/2*b*y(3)*j','Dy(3)=-d*y(3)*j+1/2*b*y(2)*j')
error('symbolic:dsolve:errmsg2','There are more ODEs than variables.')
为什么错啦,哪里有问题,

Answer 1

syms a,b,c,d； （x）
clc;clear all;
syms a b c d;
dsolve('Dy(1)=1/2*a*y(2)*j','Dy(2)=-(c+d)*y(2)*j+1/2*a*y(1)*j+1/2*b*y(3)*j','Dy(3)=-d*y(3)*j+1/2*b*y(2)*j')
error('symbolic:dsolve:errmsg2','There are more ODEs than variables.')