Calculus Help! MEDAL AWARDED!
1.) If y=x^2e^x, then dy/dx=?

A.) 2xe^x
B.) x( x+2e^x)
C.) xe^x(x+2)
D.) 2x+e^x
E.) 2x+e

Question

Calculus Help! MEDAL AWARDED!  
1.) If y=x^2e^x, then dy/dx=? 

A.) 2xe^x 
B.) x( x+2e^x) 
C.) xe^x(x+2) 
D.) 2x+e^x 
E.) 2x+e

e.cociuba · Answer

@sjerman1 I need some help here. U said u did calc. rite?

phi · Answer

do you know the product rule?

e.cociuba · Answer

Yes, it states that dy/dx is the derivative of the first function times the second plus the first function times the derivative of the second. But it's a bit confusing.

anonymous · Answer

yeah hold on, phi is brilliant when it comes to calc, by the way

e.cociuba · Answer

k :)

phi · Answer

let u = x^2  and v= e^x

now find  u v'  + v u'
where v'  and u' mean take the derivative

phi · Answer

do you know d/dx e^x ?

phi · Answer

d/dx e^x is one of the easiest derivatives .

phi · Answer

see http://www.themathpage.com/acalc/exponential.htm#expon

e.cociuba · Answer

So, dy/dx = dydx(x^2) * (e^x) + (x^2) * dy/dx(e^x)
dy/dx (x^2) is 2x
dy/dx (e^x) is e^x 
so you get:
 2x* e^x + x^2 * e^x But do i factor out x*e^x from both terms?

phi · Answer

after you get the answer, you might have to tweak it to match one of the choices.

anonymous · Answer

if im not mistaken, @phi yes you can factor out just the e^x but that doesnt really do to much

e.cociuba · Answer

K, I got xe^x(2+x) Wat do ya'll think @sjerman1 and @phi ??

phi · Answer

you have the correct result.  now it's algebra to change it to match one of the answers.

e.cociuba · Answer

Yes so it's B.) Correct?

phi · Answer

do you have bad eyes?

anonymous · Answer

i would say no

anonymous · Answer

look at the other choices

phi · Answer

K, I got xe^x(2+x)

does that match B ?

anonymous · Answer

xe^x(2+x) matches one on the list of choices...

e.cociuba · Answer

Haha um no but I do have glasses to wear sometimes lol :)

e.cociuba · Answer

Yes it matches B... Thanks guys for the help. I appericate it. Thanks @sjerman1 and @phi :)

anonymous · Answer

nooooooo. look at the other choices...

phi · Answer

If you think it matches B  you should look more carefully.

anonymous · Answer

xe^x(2+x)

A.) 2xe^x 
B.) x( x+2e^x) 
C.) xe^x(x+2) 
D.) 2x+e^x 
E.) 2x+e

e.cociuba · Answer

Opps my badd I meant to say C.) srry (typing error)

anonymous · Answer

remember since (2+x) both 2 and x are positive it doesnt matter which order you write them in -> (2+x) or (x+2)

anonymous · Answer

Good job!

e.cociuba · Answer

Haha Thanks :) Thanks for the help ;)