Matlab解一个比较复杂的微分方程组报错

用Matlab解一个比较复杂的微分方程组时报错 代码和报错信息如下

m=1825+40;
G=6.67259*10^(-11);
M=6.4171*10^23;
g=24.79;
Wm=7.088*10^(-5);
f1='Dr=V*sin(c)';
f2='Da=V*cos(c)*sin(d)/r';
f3='Db=V*cos(c)*cos(d)/(r*cos(a))';
f4='DV=1/1865-24.79*sin(c)+7.088*10^(-5)*7.088*10^(-5)*r*cos(d)*(sin(c)*cos(d)-cos(c)*sin(a)*sin(d))';
f5='Dc=1/V*(1*cos(1)/1865-24.79*cos(c)+V*V/r*cos(c)+2*7.088*10^(-5)*V*cos(a)*cos(d)+7.088*10^(-5)*7.088*10^(-5)*r*cos(d)*(cos(c)*cos(a)+sin(c)*sin(a)*sin(d))';
f6='Dd=1/V*(1*sin(1)-V*V/r*cos(c)*cos(d)*tan(a)+2*7.088*10^(-5)*V*(tan(c)*cos(a)*sin(d)-sin(a))-7.088*10^(-5)*7.088*10^(-5)*r/cos(c)*sin(a)*cos(a)*cos(d))';
[r,a,b,V,c,d]=dsolve(f1,f2,f3,f4,f5,f6,'r(0)=3520,a(0)=-0.30403,V(0)=4800,b(0)=0,d(0)=1.37924991,c(0)=0.19547687','t')

出错 dsolve (line 194)
sol = mupadDsolve(args, options);

出错 T1 (line 13)
[r,a,b,V,c,d]=dsolve(f1,f2,f3,f4,f5,f6,'r(0)=3520,a(0)=-0.30403,V(0)=4800,b(0)=0,d(0)=1.37924991,c(0)=0.19547687','t')
请问是哪里错了 还是只是因为微分方程组没解析解
![img]( https://img-mid.csdnimg.cn/release/static/image/mid/ask/558586334826137.png https://img-mid.csdnimg.cn/release/static/image/mid/ask/558586334826137.png 'BE815973-2C6B-42A6-872A-B946AF20C8F2.png'
img

微分方程的描述有很大的问题：
f1='Dr=Vsin(c)'; 应该改为 f1='Dr=Vsin(c)';
f2='Da=Vcos(c)sin(d)/r'; 应该改为f2='Da=Vcos(c)sin(d)/r'
f3='Db=Vcos(c)cos(d)/(rcos(a))'; 应该改为f3='Db=Vcos(c)cos(d)/(rcos(a))';
所有变量乘号关系的中的*是不能省略的。