Question

matlab解方程出现复数

x=solve('10^(9500*x+1.63)-10^10.35+2*10^(8700*x+3.72)=0','x')
警告: Support of character vectors that are not valid variable names or define a number will be removed in a future release. To create
symbolic expressions, first create symbolic variables and then use operations on them.
> In sym>convertExpression (line 1559)
In sym>convertChar (line 1464)
In sym>tomupad (line 1216)
In sym (line 179)
In solve>getEqns (line 405)
In solve (line 225)
警告: Do not specify equations and variables as character vectors. Instead, create symbolic variables with syms.
> In solve>getEqns (line 445)
In solve (line 225)
警告: The solutions are valid under the following conditions: FALSE.
To include parameters and conditions in the solution, specify the 'ReturnConditions' option.
> In solve>warnIfParams (line 507)
In solve (line 356)

x =

0.00072769603461595828113813268738696 - 0.0078405007457458212187236007282809i

这个x应该是个实数物理量，请问求解过程有问题吗，我是matlab小白~

Answer 1

用solve（）函数求解其方程，可以得到一个实数解和九四个虚数解。

x=0.00072670001175922463023233095120785

另一种方法，可以用fsolve（）函数

>> fun=@(x)10^(9500*x+1.63)-10^10.35+2*10^(8700*x+3.72);

>> x=fsolve(fun,0)

x=0.0007267