How do I get all solutions of the equation cos(x)==cos(3x) using solve() from Symbolic Math Toolbox ?

4 次查看（过去 30 天）
Angelo Cacini
Angelo Cacini 2018-3-25
评论： Angelo Cacini 2018-3-26
I’ve tried the following code:
syms x
h(x)=cos(x)==cos(3*x);
[sol,par,cond]=solve(h,x,'returnconditions',true)
sol =
pi*k
par =
k
cond =
in(k, 'integer')
But I expected to obtain: k*pi/2.
Where am I wrong ? Thanks in advance.

请先登录，再回答此问题。

回答（1 个）

David Goodmanson
David Goodmanson 2018-3-26
Hi Angelo,
You didn't go wrong, it's missing half of the roots. But this works
h(x)=sin(x+pi/2)==sin(3*x+pi/2);
go figure.

类别

在 Help Center 和 File Exchange 中查找有关 Symbolic Math Toolbox 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by