Calculus Help

[blingbling]

Can someone please find the 2nd derivative of this for me? It is really difficult =(

http://www.ultimatecarpage.com/forum/attachment.php?attachmentid=219106&stc=1&d=1163710100

[Sweeney921]

do you need it simplified to one fraction?

EDIT: nevermind, I think I have it, I'll make it in paint real quick.

[blingbling]

Yes please.

[Sweeney921]

I used the quotient rule and ended up with this:

all of the exponents that look kind of like 1's are really 2's

[Quiggs]

Seriously, what the hell just happened?

[blingbling]

HOLY CRAP :eek:

**brain melts**

SOLUTION TO OBTAIN THAT?

[The_Canuck]

Seriously, what the hell just happened?
You just got a massive hit of reality. Were idiots.

[Sweeney921]

HOLY CRAP :eek:

**brain melts**

SOLUTION TO OBTAIN THAT?
getting the first derivative was simple enough, but then I had to bust out the quotient rule to get the second.

first derivative:

[Quiggs]

I scored an 1190 on the SAT, carried a 3.88 GPA through a year and a half of auto school, and always did well in my math courses up to and including trig. And I am completely lost by what just happened.

[Sweeney921]

I scored an 1190 on the SAT, carried a 3.88 GPA through a year and a half of auto school, and always did well in my math courses up to and including trig. And I am completely lost by what just happened.
Math's my best subject:)

[blingbling]

BRB I GOTTA EAT

i will be back in like 20 min

[drakkie]

I hated those kind of sums,bt i had them right most of the time :) We practiced millions of these suckers... I'm too sleepy right now to check this one,will do first thing tomorrow :)

[blingbling]

tomorrow :)tomorrow... as in AFTER the midterm, when the solution is useless...

[blingbling]

^sry for sounding negative :(

just stressin out

Mr. Sweeney, can you show some solutions?

[Sweeney921]

Mr. Sweeney, can you show some solutions?
what do you mean by solutions?

[Sweeney921]

ohhh man I screwed up royally on both derivatives........didn't notice that you have to use the product rule first:o

first derivative:

[blingbling]

sorta like ... ur 'steps'

[LotusLocost]

http://www.dropshots.com/photos/136893/20060916/b_094534.jpg

:rolleyes:

I don't understand shit!!....:P so I'm officialy hi-jacking the thread:d

[Sweeney921]

1. you have to use the product rule to derive it because there's 2 different variables multiplied by one another (x and e)
2. Product rule: (derivative of first variable multiplied by the original second variable)+(derivative of second variable multiplied by the original first variable)

From there on it's all algebra, but some pretty complicated stuff. I'm not gonna attempt the second derivative, I know I'll mess it up somewhere.

[SPHFerrari]

ah i hate all the different rules. i can never keep them straight. def my worst part of math.

[blingbling]

ehhh **** this shit

[Bob]

heres first

[man 430gt]

http://www.dropshots.com/photos/136893/20060916/b_094534.jpg

:rolleyes:

I don't understand shit!!....:P so I'm officialy hi-jacking the thread:d
Lol, I'll help:D

[jediali]

my solution, use produt rule; uv'+vu'

[man 430gt]

my solution, use produt rule; uv'+vu'
:confused: Math genuis?

[Bob]

and the second its all done with the power rule, derivative of e^u rule, and product rule. Quite simple really, but a pain in the ass to make sure everything's kept straight. I haven't checked this, no guarantees.

[Bob]

my solution, use produt rule; uv'+vu'
looking at that, i might not have done the derivative of e^u correctly. but i think i did. one of us is wrong.

[man 430gt]

looking at that, i might not have done the derivative of e^u correctly. but i think i did. one of us is wrong.
Yeah I was gonna point that out but my dog was biting my leg so I was kinda of busy (;) ).

[jediali]

:confused: Math genuis?

hope this is clearer:cool:

[man 430gt]

hope this is clearer:cool:
That just hurts...

[jediali]

That just hurts...

if only my 5th engineeirng degree stuff was this inviting, this is the fun bit!:cool:

[Vaigra]

I think he mean he wants each step broken down.
I don't see how that will help you blingbling unless somebody explains it all you.

[man 430gt]

I think he mean he wants each step broken down.
I don't see how that will help you blingbling unless somebody explains it all you.
Leave it man, I'm too bloody tired to try and commit my self to anything mathematical...

[jediali]

hope this is clearer:cool:

if there is stuff you can't understand here, then you might need to look back on notes, we cant teach you all about differentiation, there is no quick solution. sorry to be a bummer if am, you are welcome to ask me/us individual questions like "how to derive an exponential function on its own".or tell us Where is it you struggle? best of luck

[Vaigra]

I remember doing all that and being very good at it. 2 years without maths of any sort and I REALLY need to refresh, thanks for the thread :)

[Zorlox]

http://www.ultimatecarpage.com/forum/attachment.php?attachmentid=219153&stc=1&d=1163722997
hope this helps. finally having a tablet comes in handy. just in case you don't trust me, mathematica's answer is attached too.

[Alastor]

looking at that, i might not have done the derivative of e^u correctly. but i think i did. one of us is wrong.

Your first derivative is the correct one.

However, is the second derivative correct? The first two components look right but the third doesn't (looking at the non-simplified form).

Should it be:

(2/x^2)e^(-1/x^2)(2/x^2)

or

(2/x^3)e^(-1/x^2)(2/x^2)

[baddabang]

Wow I am so glad I never have to take a Math course again. EvAr!!!!

[jediali]

maths is funnnn

[baddabang]

maths is funnnn

Going to the strip club is fun. Math isn't.

[drakkie]

Going to the strip club is fun. Math isn't.

Math is fun when you calculate stuff on engine and valves and those kind of stuff :D Otherwise it is boring,difficult and annoying :p

[jediali]

Math is fun when you calculate stuff on engine and valves and those kind of stuff :D Otherwise it is boring,difficult and annoying :p

that is what makes an engineering course more fun and useful than a maths course

[Bob]

Your first derivative is the correct one.

However, is the second derivative correct? The first two components look right but the third doesn't (looking at the non-simplified form).

Should it be:

(2/x^2)e^(-1/x^2)(2/x^2)

or

(2/x^3)e^(-1/x^2)(2/x^2)
Yes i did this quickly it goes like you said and the final answer comes out
((-2/x^3)+(4/x^5))e^(-1/x^2)
which is correct its the same answer given by mathematica in someone else's post. In my hurry to be done i didn't check my exponenets.

[Bob]

hope this is clearer:cool:
Your derivation of e^u is wrong.

d/dx e^u = u'e^(u)

you have it as

d/dx e^u = e^(u')

[MRR]

that is what makes an engineering course more fun and useful than a maths course

Agreed and I hate it when math teachers say just do math for the sake of math (even though I do like it). It is supposed to be a tool and applications in the real world are most important.