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Compute the fifth derivative with respect to x:
[Sin[x]Log[x]. Thanks for help.

 Dec 17, 2016

Best Answer 

 #1
avatar+129849 
+5

I'm assuming that Log (x)   is base 10

 

This can get a little messy.....here's WolframAlpha's answer........

 

 

https://www.wolframalpha.com/input/?i=fifth+derivative++%5Bsin+(x)+*+Log+(x)%5D&rawformassumption=%7B%22FunClash%22,+%22Log%22%7D+-%3E+%7B%22Log10%22%7D

 

 

 

 

cool cool cool

 Dec 17, 2016
 #1
avatar+129849 
+5
Best Answer

I'm assuming that Log (x)   is base 10

 

This can get a little messy.....here's WolframAlpha's answer........

 

 

https://www.wolframalpha.com/input/?i=fifth+derivative++%5Bsin+(x)+*+Log+(x)%5D&rawformassumption=%7B%22FunClash%22,+%22Log%22%7D+-%3E+%7B%22Log10%22%7D

 

 

 

 

cool cool cool

CPhill Dec 17, 2016
 #2
avatar+118667 
0

or if it is log base e

 

\(y=e^xsinx\\~\\ y'=e^xsinx+e^xcosx\\~\\ y''=e^xsinx+e^xcosx+e^xcosx-e^xsinx\\ y''=2e^xcosx\\~\\ y'''=2e^xcosx-2e^xsinx\\ y'''=2e^x(cosx-sinx)\\ y''''=2e^x(cosx-sinx)+2e^x(-sinx-cosx)\\ y''''=2e^x(cosx-sinx-sinx-cosx)\\ y''''=-4e^xsinx\\ y'''''=-4y'=-4e^x(sinx+cosx)\\ \)

 Dec 17, 2016
 #3
avatar+129849 
+5

If the log base is "e" ....it's more simple......but still a little messy

 

5th derivative of   f(x)   =  sin x * ln (x)

 

 It will be the same answer as before except  that we will not have any logs in the denominators :

 

d^5/dx^5(sin(x) log(x)) = (24 sin(x))/x^5 - (30 cos(x))/x^4 - (20 sin(x))/x^3 + (10 cos(x))/x^2 + (5 sin(x))/x + log(x) cos(x)

 

See Wolfram's computation, here :

 

https://www.wolframalpha.com/input/?i=fifth+derivative+%5B+sin+x+*+ln+(x)+%5D

 

 

cool cool cool

 Dec 17, 2016
 #4
avatar+118667 
0

Silly me, I answered the wrong question.  Thanks Chris :)

Melody  Dec 18, 2016

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