编程语法问题。

这样写为什么有警告呢？ dsolve('0.5*D2x==-0.2*Dx-10*x','Dx(0)=0','x(0)=0.5')

警告: Support of character vectors and

strings will be removed in a future

release. Use sym objects to define

differential equations instead.

> 位置：dsolve (第 126 行)

ans =

(exp(-t/5)*(499*cos((499^(1/2)*t)/5) + 499^(1/2)*sin((499^(1/2)*t)/5)))/998

Answer 1

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因为这种写法要过时了呗，但是目前还能用

Character vector inputs will be removed in a future release. Instead, use syms to declare variables and replace inputs such as dsolve('Dy = y') with syms y(t); dsolve(diff(y,t) == y).

新的写法如下：

syms x(t) a

eqn = 0.5*diff(x,t,2) == -0.2*diff(x,t)-10*x;

Dx = diff(x,t);

cond = [Dx(0)==0 x(0)==0.5];

dsolve(eqn,cond)