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Mathematics 7 Online
OpenStudy (anonymous):

EVALUATE ..... =_=

OpenStudy (anonymous):

\[ \lim_{x \rightarrow \infty} ( 1+ \frac{ 3 }{x })^{x}\]

OpenStudy (anonymous):

in the future put the question in the question box please

OpenStudy (anonymous):

oh yay. this is one of those derpy ones. go look at the definition of e ;)

OpenStudy (anonymous):

>_ >

hartnn (hartnn):

do you know the standard limit formula, \(\lim_{x \rightarrow 0} ( 1+ x)^{1/x}=...?\)

OpenStudy (anonymous):

no thats new

hartnn (hartnn):

to bring it in that form, first you need to put x=1/y so that as x->infinity, y->0

hartnn (hartnn):

\[\lim_{x \rightarrow 0} ( 1+ x)^{1/x}=e\]

OpenStudy (anonymous):

is that a rule !!! we just follow it

hartnn (hartnn):

put x=1/y what u get ?

hartnn (hartnn):

yes, but your Q is not exactly that rule/formula..so answer isn't =e

OpenStudy (anonymous):

I got ∞ as an answer

OpenStudy (anonymous):

i got one as answer -.-

hartnn (hartnn):

how 1 ?

hartnn (hartnn):

both are incorrect :P

OpenStudy (anonymous):

i will show u :] .. simple and smart

hartnn (hartnn):

*waiting eagerly*

OpenStudy (anonymous):

:3

OpenStudy (anonymous):

\[limx→∞(1+3x)^x \] \[=(1+\frac{ 3 }{ \infty } )^{\infty} \] \[= 1^{\infty} = 1\]

OpenStudy (anonymous):

:)

hartnn (hartnn):

lol

OpenStudy (anonymous):

exactly

hartnn (hartnn):

1^infinity is undefined...

OpenStudy (anonymous):

:I who said that

OpenStudy (anonymous):

try it on ur calculator >:[

hartnn (hartnn):

i did now......and all the mathematicians did it already..

hartnn (hartnn):

trust me 1^infinity is not defined...

hartnn (hartnn):

tell me what u get after u put x=1/y

OpenStudy (anonymous):

okie -.-

OpenStudy (anonymous):

so the answer is ?

hartnn (hartnn):

you want answer or you want to know how to get it ?

OpenStudy (anonymous):

de second choice

hartnn (hartnn):

tell me what u get after u put x=1/y

OpenStudy (anonymous):

what is y ?

OpenStudy (anonymous):

function ?

hartnn (hartnn):

a new vaiable so that i can bring your limit in standard form.

hartnn (hartnn):

*variable

hartnn (hartnn):

in your limit, x-> infinity standard form, x->0 so i put x=1/y so that y->0 now..

OpenStudy (anonymous):

y = ( 1+ 3/x) ?

OpenStudy (anonymous):

=.=

hartnn (hartnn):

you can choose any variable to put in place of 1/x 'y' or 'u' or 't' or even 'Alice_Dump' Alice_Dump = 1/x Alice_Dump ->0

OpenStudy (anonymous):

xDD

hartnn (hartnn):

bdw, y=1/x

OpenStudy (anonymous):

okie

hartnn (hartnn):

so, your limit in terms of y is ?

OpenStudy (anonymous):

TT^TT

OpenStudy (anonymous):

just let me me think okie -.-

hartnn (hartnn):

sure, take your time :)

OpenStudy (anonymous):

is it ...... \[\frac{ 1 }{ 1+ \frac{ 3 }{x } }\] ??

OpenStudy (anonymous):

is that what u mean .!!

OpenStudy (anonymous):

-.....-

hartnn (hartnn):

no...

OpenStudy (anonymous):

XD

OpenStudy (anonymous):

-.-

OpenStudy (anonymous):

im still looking for it too...

OpenStudy (anonymous):

i give up thinking -_-

OpenStudy (anonymous):

show me de solution

hartnn (hartnn):

3/x = 3(1/x) = 3y so, wait....

OpenStudy (anonymous):

and i'll seee how u did it

OpenStudy (anonymous):

ohh okie ..

OpenStudy (anonymous):

i get it now

hartnn (hartnn):

\[\lim_{x \rightarrow \infty} ( 1+ \frac{ 3 }{x })^{x}\\=\lim_{y \rightarrow 0} ( 1+ 3y )^{1/y} \\ =\lim_{y \rightarrow 0} [( 1+ 3y )^{1/3y}]^3\] did you get the last step ??

OpenStudy (anonymous):

i got the answer e^3

OpenStudy (anonymous):

So its multiplied?

hartnn (hartnn):

e^3 is correct!

hartnn (hartnn):

food :)

hartnn (hartnn):

i meant good :) lol

OpenStudy (anonymous):

YAY alice got it

OpenStudy (anonymous):

O3O thanks to u

OpenStudy (anonymous):

xD

OpenStudy (anonymous):

X3 i fail

OpenStudy (anonymous):

congrats guys! :D

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