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Adam B

Why is Mathematica switching my subtraction terms inside a Trig function?

Adam B
Posted 9 years ago
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Greetings,

I'm trying to do some basic trigonometric partial derivatives in Mathematica, and for some reason it is switching my subtraction terms inside the Cos or Sin and giving me an incorrect answer. Why is it doing this? Thanks~

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POSTED BY: Adam B
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I still don't see what is incorrect.

In[1]:= D[Cos[x - c t], t]

Out[1]= -c Sin[c t - x]
POSTED BY: Ilian Gachevski

Cos is an even function. What is incorrect about the answer?
POSTED BY: Ilian Gachevski
Adam B
Adam B
Posted 9 years ago

Well what ends up happening is when I take the partial derivative of the function (with respect to t), it gives me the wrong (negative) derivative because the inside terms have switched signs.
POSTED BY: Adam B
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