Differentation problem, when trying to diff sin(f(x)) with variable x

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Andy 2014-4-26

关闭： Walter Roberson 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)

I attach a picture, to see what my problem is.

Please tell me what is wrong with my little code! Thank you!

Walter Roberson 2014-4-27

此问题已关闭。

此问题已关闭。

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