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Mathematics 7 Online
OpenStudy (fanduekisses):

HELP How do you find the limit of this?

OpenStudy (fanduekisses):

\[\lim_{\theta \rightarrow 0}\frac{ \sin \theta }{ \theta + \tan \theta }\]

OpenStudy (fanduekisses):

I figured I should replace tan theta with sin theta/cos theta

OpenStudy (fanduekisses):

\[\lim_{\theta \rightarrow 0}\frac{ \sin \theta }{ \theta + \frac{ \sin \theta }{ \cos \theta } }\]

OpenStudy (jdoe0001):

hmm

OpenStudy (chillout):

L'hospital shouldn't be allowed for his task though.

OpenStudy (fanduekisses):

We haven't seen L'Hospital yet

OpenStudy (fanduekisses):

I think I should get everything in terms of sinx or cosx

OpenStudy (jdoe0001):

hmmm yeah... L'Hopital is pretty much for this case, a 0/0 case BUT ..hmm decoupling it... doesn't seem to be lending so easy =(

OpenStudy (dinamix):

@jdoe0001 lol why

OpenStudy (jdoe0001):

well, as he/she said, they're not using L'Hopital yet

OpenStudy (dinamix):

when u are in exam what u use ?

OpenStudy (chillout):

algebraic manipulations, of course.

OpenStudy (dinamix):

\[\lim_{x \rightarrow 0}\frac{ \sin(x) }{ x+\frac{ \sin(x) }{ \cos(x)} } = \lim_{x \rightarrow 0}\frac{ 1 }{ \frac{ x }{ \sin(x) } +\frac{ 1 }{ \cos(x) }}=\lim_{x \rightarrow 0}\frac{ 1 }{ 0+1 }=1\]

OpenStudy (dinamix):

@ChillOut @jdoe0001 look my other method

OpenStudy (mathmath333):

incorrect

OpenStudy (dinamix):

lol really @mathmath333 show me my mistake

OpenStudy (mathmath333):

\(\lim_{x \rightarrow 0}\frac{ \sin(x) }{ x+\frac{ \sin(x) }{ \cos(x)} } = \lim_{x \rightarrow 0}\frac{ 1 }{\color{red}{ \frac{ x }{ \sin(x) }} +\frac{ 1 }{ \cos(x) }}=\lim_{x \rightarrow 0}\frac{ 1 }{ 0+1 }=1\)

OpenStudy (anonymous):

lim x/sin(x) = 1, so the entire limit is 1/2

OpenStudy (mathmath333):

moreover the answer comming through L'hopital's rule is \(\dfrac{1}{2}\)

OpenStudy (dinamix):

hmm i made mistake i know where is it

OpenStudy (chillout):

You almost got it right though

OpenStudy (anonymous):

\[\lim_{x \rightarrow 0}\frac{ \sin(x) }{ x+\frac{ \sin(x) }{ \cos(x)} } = \lim_{x \rightarrow 0}\frac{ 1 }{ \frac{ x }{ \sin(x) } +\frac{ 1 }{ \cos(x) }}=\lim_{x \rightarrow 0}\frac{ 1 }{ 1+1 }=\frac{ 1 }{2 }\]

OpenStudy (dinamix):

yup i made mistake @bts30 i know why u steal my solution lol

OpenStudy (chillout):

Noone's stealing. Don't worry if you want Little Stars!

OpenStudy (dinamix):

xD

OpenStudy (dinamix):

@mathmath333 @bts30 ty both for see my solution

OpenStudy (dinamix):

@Fanduekisses u understand how i solve it

OpenStudy (fanduekisses):

@dinamix Sorry I left.

OpenStudy (fanduekisses):

@dinamix how did you get the 2nd part?

OpenStudy (fanduekisses):

lim x-> 0 of 1/x/sinx + 1/cosx?

OpenStudy (dinamix):

its just simplif sin(x) only

OpenStudy (fanduekisses):

How did you get the denominator?

OpenStudy (dinamix):

hmm i use sin(x)/sin(x) = 1 right ?

OpenStudy (fanduekisses):

sinx/x

OpenStudy (dinamix):

did u understand now how i get denominator

OpenStudy (fanduekisses):

no :( how did you get x/sinx? where did the sinx come from? and how did you get 1/cosx? the denominator was originally x+ sinx/cosx how did it change?

OpenStudy (dinamix):

sin(x)x/sin(x) = x right ?

OpenStudy (fanduekisses):

yes

OpenStudy (chillout):

he divided both the upper and lower parts by sin(x). That's what he did.

OpenStudy (fanduekisses):

:s

OpenStudy (dinamix):

ty for @ChillOut explain

OpenStudy (fanduekisses):

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