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Posted: 5/4/2015 5:31:27 PM EDT
Does the chain rule work for trigonometric functions?

df/dt = df/dp * dp/dq * dq/dt

If f(t) = Cos^2(wt)   <--- supposed to be cosine-squared (cosine(wt) * cosine(wt))

f(p) = p^2

p(q) = Cos(q)

q(t) = wt


Is this correct?

d/dt [Cos^2(wt)] = 2*Cos(wt) * (-Sin(wt)) * (w)


Now that I have typed this out I am certain it is true and that the chain rule works just fine for trig functions.   Please confirm for me, or tell me I stupid  but then give the correct answer.



ETA - I just noticed the effective frequency of Cos^2(wt) is double that of Cos(wt).
Link Posted: 5/4/2015 6:39:19 PM EDT
[#1]
Looks correct, but it's been 12 years since my last calc class.
Link Posted: 5/4/2015 7:24:43 PM EDT
[#2]
Link Posted: 5/5/2015 12:09:32 AM EDT
[#3]
Thank you, guys.
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