MATLAB 示例失败

Question

我完全不知道这里发生了什么，Google 也没有提供有趣的帮助。我从 http://www.mathworks.com/help/toolbox/symbolic/solve.html#inputarg_eqn 中获取了以下示例

>> syms x
>> solve(x^2 + 4*x + 1 == 0)
??? Error using ==> char
Conversion to char from logical is not possible.

Error in ==> solve>getEqns at 169
   vc = char(v);

Error in ==> solve at 67
[eqns,vars] = getEqns(varargin{:});

这是怎么回事？

Answer 1

您正在阅读的文档不适用于您的 MatLab 版本。例如，我可以在 2008b 中重现您的错误。

旧文档说:

Note that these examples assume equations of the form f(x) = 0. If you need to solve equations of the form f(x) = q(x), you must use quoted strings. In particular, the command

s = solve('cos(2*x)+sin(x)=1')

以后，请注意每个 MatLab 在线文档页面顶部的行，其中说明该文档适用于哪个版本。