Question

just need someone to confirm my answers....use substitution e^(x)=u to valuate the integral e^(x)/(1+e^(x)) dx

Answer 1

So du=e^x dx
\[\int\limits \frac{du}{1+u}\]
Let s=1+u
ds=du
\[\int\limits \frac{ds}{s}=\ln|s|+C \rightarrow \ln|u+1|+C \rightarrow \ln|e^x+1|+C\]

Answer 2

\[\int\limits_{}^{}\frac{du}{u}, with u=e^x+1 => du=e^x dx\]

Answer 3

lol

Answer 4

\[withu\]

Answer 5

i wonder why they want you to use u=e^x not u=e^x+1

Answer 6

It said let u=e^x thats why I did it that way.

Answer 7

i know male

Answer 8

cant make a difference can it? since 1 is a number i mean

Answer 9

i just don't know why they would ask you to use that substitution

Answer 10

ya that's the problem says it's supposed to be. this teacher likes to give hard to impossible problems tho so i figured i'd double check

Answer 11

i mean its okay but i like mine more

Answer 12

you better hurry before saifoo becomes a sensei

Answer 13

hey satellite what number of medals do i need to get to sensei level?