Yet another limit question in this forum.

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Ballox
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Homework Statement


limx->0+ [tan([tex]\sqrt{x}[/tex])-sin([tex]\sqrt{x}[/tex])] / x[tex]\sqrt{2x}[/tex]

Homework Equations


tanx= sinx/cosx

The Attempt at a Solution


I set u= [tex]\sqrt{x}[/tex]
Therefore as a->0, u->0

And I get the limit
=lim x->0+ (tan([tex]\sqrt{x}[/tex])-sin([tex]\sqrt{x}[/tex]))/ (x*[tex]\sqrt{2}[/tex]* [tex]\sqrt{x}[/tex])
= 1/[tex]\sqrt{2}[/tex]lim u->0 (tan(u)-sin(u))/u3
= 1/[tex]\sqrt{2}[/tex]lim u->0 (sin(u)-sin(u)cos(u))/ (cos(u)*u3)
= 1/[tex]\sqrt{2}[/tex]lim u->0 sin(u)(1-cos(u))/(cos(u)*u3)

And it is here where I'm stuck. I'm not sure what to do next =\
We haven't learned L'hopital's rule yet, so if it's needed, it really shouldn't be applied.

I'm open to any suggestions and I thank you for your time,

Ballox
 
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Hmm. I do know that. I'll see what I can do.
Thanks for the hint.
 
micromass said:
Do you know the limit [tex]\lim_{x\rightarrow 0}{\frac{sin(x)}{x}}=1[/tex], if yes, you can apply this two times here...

Alright, so I just did it again...
And in fact I was able to apply that theorem THREE times.

My final answer was 1/2[tex]\sqrt{2}[/tex]

Would this answer be correct?
 
micromass said:
That looks about right :smile:

Thank you kindly for your help.