Question

matlab中sym和findsy及maple几个函数什么意思

Answer 1

sym是将 字符串和数值转换为 字符变量

比如

>> xx=sym('x+y')
class(xx)

xx =

x + y

ans =

sym

findsys 则是找出字符号表达式中的自变量

比如

findsym(xx)

ans =

x,y

findsym(S) for a symbolic expression or matrix S, returns all symbolic variables in S in lexicographical order, separated by commas. If S does not contain any variables, findsym returns an empty string.

findsym(S, n) returns the n variables alphabetically closest to x:

1.

The variables are sorted by the first letters in their names. The ordering is x y w z v u ... a X Y W Z V U ... A. The name of a symbolic variable cannot begin with a number.
2.

For all subsequent letters the ordering is alphabetical, with all uppercase letters having precedence over lowercase: 0 1 ... 9 A B ... Z a b ...z.

findsym(S) can return variables in different order thanfindsym(S, n).

maple函数 MATLAB7.7之前版本提供的一个执行maple内核符号运算的函数，因为7.7之前的版本符号工具箱内容使用的是Maple，不过之后使用的是MuPAD，因此maple函数也取消了