I want to differentiate the following vector:

$$=\frac{1}{\sqrt{a^2\omega^2\sin^2(\omega t)+b^2\omega^2\cos^2(\omega t)}}\begin{pmatrix}-a \omega \sin(\omega t)\\b \omega \cos (\omega t)\end{pmatrix}$$

However if I type this into mathematica then mathematica doesn't recognize that $\omega$ and $a,b$ are constants. Any idea how I can tell mathematica that they are constants?


closed as off-topic by m_goldberg, Karsten 7., user9660, Kuba, Sjoerd C. de Vries Oct 18 '15 at 14:10

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  • $\begingroup$ There are at least to direct hits within Mathematicas Help Constants and Local Constants and Constant $\endgroup$ – user9660 Oct 18 '15 at 12:58
  • $\begingroup$ Look up Constant in the Documentation Center. $\endgroup$ – m_goldberg Oct 18 '15 at 12:59

I'm not sure I see why you need to? Simply differentiate only with respect to t, as follows:

enter image description here

then: enter image description here

If you do ned to tell Mathematica they are constants then as Lou and m_goldberg have said use:

    SetAttributes[{a, b, ω}, Constant]
  • $\begingroup$ Thanks! I just realized I am an idiot for using the wolfram alpha input in mathematica and not the actual mathematica input. Thanks for your help! $\endgroup$ – bluemoon Oct 18 '15 at 13:16

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