Question

用MATLAB解复杂的微分方程 (急!!!)

请问如何用MATLAB解复杂的微分方程 (急!!!)谢谢写出程序和方法!!谢谢!!! 要解的方程如下: -dy/dx=1/(k1*exp((m+n)*y)+(k3*exp(m*y)+k7*exp(m*y))/(k1*k2*exp((m+n)*y))/x

Answer 1

你这个方程应该算不出来吧
而且你的括号也些漏了一个
你自己数一下究竟是哪里漏了,
我在等式的最后写上括号是的方程变成
-dy/dx=1/(k1*exp((m+n)*y)+(k3*exp(m*y)+k7*exp(m*y))/(k1*k2*exp((m+n)*y))/x)
代码为:
dsolve('-Dy=1/(k1*exp((m+n)*y)+(k3*exp(m*y)+k7*exp(m*y))/(k1*k2*exp((m+n)*y))/x)','x')
这样得到的结果是
Warning:
Explicit
solution
could
not
be
found.
>
In
dsolve
at
333
In
Untitled
at
11
ans
=
[
empty
sym
]
用Mathematica算了一遍还是没有找到结果
下面是Mathematica的代码
DSolve[-y'[x]
==
1/(k1*Exp[(m
+
n)*y[x]]+
(k3*Exp[m*y[x]]+
k7*Exp[m*y[x]])/(k1*k2*Exp[(m
+
n)*y[x]])/x),
y[x],
x]
得到的结果是:
Solve::tdep:
The
equations
appear
to
involve
the
variables
to
be
solved
for
in
an
essentially
non-algebraic
way.
>>
DSolve[-
\!\(\*SuperscriptBox["y",
"\[Prime]",
MultilineFunction->None]\)[x]
==
1/(
E^((m
+
n)
y[x])
k1
+
(
E^(-(m
+
n)
y[x])
(E^(m
y[x])
k3
+
E^(m
y[x])
k7))/(k1
k2
x)),
y[x],
x]