MATLAB，关于solve函数的报错

piday123

我在学习matlab符号运算这一章时尝试把书本的例子输入，发现是有误的，以下是从发现到修改的过程。
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**在这里>> a = sym('a');
>> b = sym('b');
>> x = sym('x');
>> y = sym('y');
>> [x,y] = solve('a*x-b*y=1','a*x+b*y=3','x','y')**


Error using solve>getEqns (line 418)
7 _7 B1 i) u5 z" [* c; `List of equations must not be empty.

$ l/ _& n7 z! F/ [7 UError in solve (line 226)
[eqns,vars,options] = getEqns(varargin{:});
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**>> [x,y] = solve('a*x-b*y=1''a*x+b*y=3','x','y')%第二次尝试修改**
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) }# x% g& G6 oError using solve>getEqns (line 418)
/ _, g1 r( z) b- L3 L: I: RList of equations must not be empty.
/ l8 c5 e5 D: fError in solve (line 226)
! h8 y% ~- A, t3 Y  c$ O" ?( X[eqns,vars,options] = getEqns(varargin{:});
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>> [x,y] = solve(a*x-b*y=1,a*x+b*y=3,x,y) %第三次尝试修改
) T' ~7 y  Y- x# x/ S7 Y [x,y] = solve(a*x-b*y=1,a*x+b*y=3,x,y)


**
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+ S  _6 t1 K- }4 oError: Incorrect use of ‘=’ operator. To assign a value to a variable, use ‘=’. To compare values for equality, use ‘==’.

>> [x,y] = solve(a*x-b*y== 1,a*x+b*y==3,x,y)%最终成功
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* S! d5 N3 T9 A& w) m1 Wx =
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2/a
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( q" `" Z( ~3 E% h8 c; `% ay =

1/b
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CCxiaom

这个感觉比较有用