Problem, when trying to differentate sin(f(x)), with variable x

1 次查看（过去 30 天）
Andy
Andy 2014-4-26
评论： Azzi Abdelmalek 2014-4-27
Hello!
I would like to try some basic functions in Matlab. I faced two problems, which seems unable to solve for me.
If I type:
a=sin(3*x)
b=diff(a,x)
Then I run it:
a=sin(3*x)(3*x)
b=3*D(sin(3*x))(3*x)
I think it should be:
a=sin(3*x)
b=3*cos(3*x)
Please tell me what is wrong with my little code! Thank you!

请先登录，再回答此问题。

采纳的回答

Azzi Abdelmalek
Azzi Abdelmalek 2014-4-26
syms x
a=sin(3*x)
b=diff(a,x)
The result is
b =
3*cos(3*x)

更多回答（5 个）

Andy
Andy 2014-4-26
Please look at the picture attached! You will see what my problem is. Do you have any idea what's wrong?
Andy
Andy 2014-4-26
Walter Roberson
Walter Roberson 2014-4-27
I think maybe you had something in your workspace that was interfering. Did you try clearing all variables, or restarting MATLAB?
Roberto
Roberto 2014-4-27
try clearing the workspace
>> clear all;
Andy
Andy 2014-4-27
Thank you! Clearing my workspace solved the problem.

类别

在 Help Center 和 File Exchange 中查找有关 Special Values 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by