A question related to subs in ode (symbolic maths toolbox)

16 次查看（过去 30 天）
Angus Wong
Angus Wong 2019-7-3
评论： Angus Wong 2019-7-3
I have a line:
ode=diff(y,x)==x+y;
I want matlab to calculate diff(a,b), given a and b are real numerical values. However, the subs function allowed me only to either sub the value a or value b into the ode line, can anyone help?
I am expecting something like subs(ode,[x,1,y,2]) would give me 3, subs(ode,[x,4,y,5]) would give me 9.

请先登录，再回答此问题。

采纳的回答

madhan ravi
madhan ravi 2019-7-3
I am not sure what you are asking for perhaps an example below?:
>> syms x y
>> eqn = x+2*y
eqn =
x + 2*y
>> subs(eqn,{x,y},{2,5})
ans =
12
>>
  2 个评论
madhan ravi
madhan ravi 2019-7-3
Perhaps ?:
>> syms y(x)
>> ode=diff(y,x)==x+y;
>> subs(rhs(ode)-lhs(ode),{x,y},{1,2})
ans(x) =
3
>> subs(rhs(ode)-lhs(ode),{x,y},{4,5})
ans(x) =
9
>>

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Symbolic Math Toolbox 的更多信息

标签

产品


版本

R2019a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by