Question

matlab计算三角函数方程

[a,t]=solve('2600*sina=9.8*t','1300*1300*sin(2*a)=9.8*111770')怎么无法算出答案啊，求大佬解答老是警告: Support of strings 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 1536)
In sym>convertChar (line 1441)
In sym>tomupad (line 1198)
In sym (line 177)
In solve>getEqns (line 405)
In solve (line 225)
警告: Do not specify equations and variables as character strings. Instead, create symbolic variables with syms.
> In solve>getEqns (line 445)
In solve (line 225)

Answer 1

可以算的，你的sina要改成sin(a)，matlab才会认同，然后新的版本matlab不建议你直接使用符号变量，而是要先申明，所以会有一些警告，但是有计算结果，如下：
[a,t]=solve('2600*sin(a)=9.8*t','1300*1300*sin(2*a)=9.8*111770')
结果W为：
a =

1.2182307396525019002681606902101
0.35256558714239471896316100142965

t =

248.98711314846040879006807025518
91.611986633347967995305036408499