Are My Calculus Derivatives Correct?

[eeyore81]

For both questions i have to find dy/dx
1. y=x^5e^-3x

I got (5x^4 e^-3x) + (x^5 (-3xe^-3x-1))

some how that doesn't look right to me. not too sure...

2.
1-e^-x
y= --------
1+e^2x
My answer was:


(e^-x) - (1-e^-x) (2xe^2x-1)
y'= -----------------------------
1+e^2x


Thanks for your help! It's much appreciated!

 

[dextercioby]

For both questions i have to find dy/dx
1. y=x^5e^-3x
I got (5x^4 e^-3x) + (x^5 (-3xe^-3x-1))
some how that doesn't look right to me. not too sure...
2.
1-e^-x
y= --------
1+e^2x
My answer was: (e^-x) - (1-e^-x) (2xe^2x-1)
y'= -----------------------------
1+e^2x
Thanks for your help! It's much appreciated!

1.It's wrong.It is an "x" too much.Figure out where.
2.It's wrong.Again an "x" too much,a 'minus' missing,a whole term missing and a sqare on the denominator.Figure it out yourself.

Daniel.

 

[eeyore81]

First of all, thanks for replying, I'm still working on fixing the 2nd question, but i think i got the first one, the answer should be:


y' = (5x^4 e^-3x) + (x^5 -3e^-3x)