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Mathematics 6 Online
OpenStudy (anonymous):

Find dy/dx step by step? please? :)

OpenStudy (anonymous):

\[y=ln(\frac{ x^4e^{3x} }{ \sqrt{2x^5-1} })\]

OpenStudy (anonymous):

yuck!!!

OpenStudy (anonymous):

I know ;(

OpenStudy (anonymous):

i think it would be better to do logarithmic differentiation...

OpenStudy (anonymous):

\(\large y=ln(\frac{x^4e^{3x}}{(2x-5)^{\frac{1}{2}}}) = 4lnx + 3x - \frac{1}{2}(2x^5-1)\) simplifying y that way should be much simpler...

OpenStudy (anonymous):

i guess that's not so hard afterall....

OpenStudy (anonymous):

wait wait.. how'd you get 4ln(x)+3x-1/2(2x^5-1)

OpenStudy (anonymous):

use the logaritm properties...

OpenStudy (anonymous):

I need to look those up ;/ and review them.

OpenStudy (anonymous):

\(\large ln(AB)=lnA+lnB \); \(\large ln(A/B)=lnA-lnB \); \(\large ln(A^B)=BlnA \); hmm... i think that's all of 'em...

OpenStudy (anonymous):

Awe, well thank you. Okay so now back to what you got.. Let me look over that real quick

OpenStudy (anonymous):

yeah... should be easier now....

OpenStudy (anonymous):

Okay so I see you used the second one.. But, I'm confused how you got those values... ln(A)=4lnx+3x when A= x^4e^{3x}

OpenStudy (anonymous):

is it..ln(x^4)=4lnx

OpenStudy (anonymous):

\(\large y=ln(\frac{x^4e^{3x}}{(2x-5)^{\frac{1}{2}}}) =ln(x^4e^{3x})-ln(2x-5)^{1/2} \)

OpenStudy (anonymous):

that's the first step...

OpenStudy (anonymous):

now.... \(\large ln(x^4e^{3x})=lnx^4+lne^{3x}=4lnx+3x \) do u undestand this part?

OpenStudy (anonymous):

ooo... sorry my bad... the second part is wrong....

OpenStudy (anonymous):

ohhh... ln(A^b)=b*ln(A) ln(x^4)=4*ln(x) and e&ln cancel out leaving 3x

OpenStudy (anonymous):

\(\large ln(2x-5)^{1/2}=\frac{1}{2}ln(2x-5) \) that's what it should have been...

OpenStudy (anonymous):

and yes (to your last post)

OpenStudy (anonymous):

lemme rewrite what i shouldve written....

OpenStudy (anonymous):

\(\large y=ln(\frac{x^4e^{3x}}{(2x-5)^{\frac{1}{2}}}) = 4lnx + 3x - \frac{1}{2}\color {red}{ln}(2x^5-1) \)

OpenStudy (anonymous):

\[\frac{ 4 }{ x }+3..\]

OpenStudy (anonymous):

yep... keep going...

OpenStudy (anonymous):

I need to do chain rule?

OpenStudy (anonymous):

yes, chain rule: \(\large [lny]'=\frac{y'}{y} \)

OpenStudy (anonymous):

so \(\large [ln(2x^5-1)]'=\frac{[2x^5-1]'}{2x^5-1} \) simplify....

OpenStudy (anonymous):

\[\frac{ 4 }{ x }+3-\frac{ 1 }{ 2 }\frac{ 10x^4 }{ 2x^5-1 } = \frac{ 4 }{ x }+3-\frac{ 5x^4 }{ 2x^5-1 }\]

OpenStudy (anonymous):

haha... looks good..:)

OpenStudy (anonymous):

why haha? did I do something wrong?

OpenStudy (anonymous):

no... i was getting the wrong answers until at the last moment when u posted ur answer... it confirmed my last answer...

OpenStudy (anonymous):

oh lol :) you just discouraged me! >;[ no im jk ;) thank you!

OpenStudy (anonymous):

oh wait...

OpenStudy (anonymous):

haha... just kidding.... yw... :)

OpenStudy (anonymous):

haha! jerk ;D

OpenStudy (anonymous):

:)

OpenStudy (anonymous):

i forgot... nice work on your part... way to stick with the problem....

OpenStudy (anonymous):

what you mean? I always finish ;D

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