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Mathematics 8 Online
OpenStudy (anonymous):

Hard Calculus Problem.

OpenStudy (anonymous):

\[\int\limits_{?}^{?} e ^{x}(1+e ^{-2x})\]

OpenStudy (anonymous):

Substitution will do..

OpenStudy (anonymous):

Let \(e^x = t\)..

OpenStudy (anonymous):

\(e^x \cdot dx = dt\)

OpenStudy (anonymous):

They left a hint saying multiply it out

OpenStudy (anonymous):

But lets try your way

OpenStudy (anonymous):

Let us try both. :P

OpenStudy (amistre64):

i was gonna suggest expanding it as well ...

OpenStudy (anonymous):

Can you show that way please

OpenStudy (amistre64):

\[e^x(1+e^{-2x})\] \[e^x+e^{-2x+x}\] \[e^x+e^{-x}\]

OpenStudy (anonymous):

\[\int\limits(e^x(1+ e^{-2x})) dx = \int\limits (1+ t^{-2})dt\]

OpenStudy (anonymous):

Then what amistre and continue only to chat

OpenStudy (anonymous):

yeah I know Mods are quite faster than me..

OpenStudy (anonymous):

Yeah but you are showing different methods

OpenStudy (amistre64):

then you integrate .. you should have a list/table of antiderivatives if anything. e^x is a very basic and simple one

OpenStudy (anonymous):

so what is the antiderivative of that?

OpenStudy (amistre64):

onlys method is working fine :)

OpenStudy (amistre64):

if you dont know the antiderivative of e^x by now then you will have to review your material.

OpenStudy (anonymous):

Can you finish though

OpenStudy (amistre64):

no, i will not do all the work for you. that is not the intentions of this site.

OpenStudy (amistre64):

you may attempt it, and we can correct as needed tho

OpenStudy (anonymous):

Please I know the answer, I just want to see if you get it

OpenStudy (anonymous):

The final answer is 2sinh(x)+c I see no possible way in getting that. @amistre64

OpenStudy (amistre64):

if thats the 'correct' solution. then they are expecting you to know hyperbolic trig stuff as well

OpenStudy (amistre64):

lets step thru it tho: what does e^x + e^-x integrate into? then we cam work it into the hyper stuff

OpenStudy (anonymous):

isn't it the same thing?

OpenStudy (anonymous):

but with a -1 outside

OpenStudy (amistre64):

the sites lagging on my end so responses are getting jumbled. if we know the hyperbolic derivatives, then converting the e^x + e^-x into its hyperbolic equivalent would work all the same

OpenStudy (anonymous):

We never went into hyper stuff so its fine

OpenStudy (anonymous):

Yes but the exam is not expecting me to know that

OpenStudy (amistre64):

e^x integrates to e^x e^-x is from -e^-x yes so our integration gets us: e^x - e^-x but then we still need to know how our hyperbolic functions are defined in terms of e

OpenStudy (amistre64):

and a +C of course

OpenStudy (amistre64):

did you get your solution from the wolf, or from your material?

OpenStudy (anonymous):

Its impossible since Rutgers University never thought us in calculus

OpenStudy (anonymous):

ty so much

OpenStudy (amistre64):

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