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。


**在这里>> a = sym('a');
>> b = sym('b');
>> x = sym('x');
! Y9 j( S% ~( K, x, X. i1 `>> y = sym('y');
) w# u6 V  w  K5 \/ l/ r>> [x,y] = solve('a*x-b*y=1','a*x+b*y=3','x','y')**
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5 ^/ {" k# L4 D5 e. GError using solve>getEqns (line 418)
List of equations must not be empty.

$ p7 g: T  T2 U# VError in solve (line 226)
' ]9 y6 x" I* V  S, H5 u7 }( V[eqns,vars,options] = getEqns(varargin{:});

2 c% ^+ z+ l1 g! i0 a; V6 @**>> [x,y] = solve('a*x-b*y=1''a*x+b*y=3','x','y')%第二次尝试修改**

3 q# G4 W' b4 E% v1 s2 [- O: JError using solve>getEqns (line 418)
List of equations must not be empty.
Error in solve (line 226)
[eqns,vars,options] = getEqns(varargin{:});

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  b2 @6 O* A) \% k* ^% X>> [x,y] = solve(a*x-b*y=1,a*x+b*y=3,x,y) %第三次尝试修改
[x,y] = solve(a*x-b*y=1,a*x+b*y=3,x,y)


**
↑
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Error: 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

, ?: ~% |) l! m2 Kx =
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2/a

% a$ y. p5 U# @) Ty =
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CCxiaom

这个感觉比较有用