# Thread: help haya with maths thread

1. ## help haya with maths thread

hey folks! switched career paths from med focus to maths focus, started maths this sem after 3 years lol.

will post q's, any help appreciated

1. find 8th derivative of exp(-sqrt3t).sint

i got 2^7.sqrt3(exp(-sqrt3t)sint)

am i right?

2. ## Re: help haya with maths thread

I'd like to see your working, otherwise wolframalpha can easily answer your question.

I'm highly skeptical of that answer due to it's simplicity and given this:

\begin{align*} y = e^{-\sqrt{3t}}\sin t \Rightarrow \ln y &= -\sqrt{3t} + \ln( \sin t) \\ \Rightarrow \frac{dy}{dt} \frac{1}{y} &= -\frac{3}{2\sqrt{3t}} + \cot t \\\Rightarrow \frac{dy}{dt} &= \left( -\frac{3}{2\sqrt{3t}} + \cot t \right )(e^{-\sqrt{3t}}\sin t)\end{align*}

which yields more doubt.

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