limits with sin

gcfan4life1023

New member
Joined
Oct 11, 2005
Messages
17
the problem is find lim as x goes towards 0 of sinx/ 3x
I know that the limit of x as x heads toward 0 of sin x/x is one but what about htis can somebody please help me this is my last question
 
\(\displaystyle \L
\frac{{\sin (x)}}{{3x}} = \frac{1}{3}\left( {\frac{{\sin (x)}}{x}} \right)\)
 
Good work! You remembered exactly the result they're expecting you to use here! :wink:

You've got this:


. . . . .\(\displaystyle \large{\begin{array}{c}limit\\x\rightarrow 0\end{array}\,\, \frac{\sin{(x)}}{x}\, =\, 1}\)


Now they've asked you to consider this:


. . . . .\(\displaystyle \large{\begin{array}{c}limit\\x\rightarrow 0\end{array}\,\, \frac{\sin{(x)}}{3x}}\)


Rearrange the expression as follows:


. . . . .\(\displaystyle \large{\frac{\sin{(x)}}{3x}\, =\,\left(\frac{1}{3}\right)\,\left(\frac{\sin{(x)}}{x}\right)}\)


Factor the "1/3" to before the "limit", and use the previous result to find this limit's value.

Eliz.

Note: You will very likely shortly encounter things like this:


. . . . .\(\displaystyle \large{\begin{array}{c}limit\\\theta\rightarrow 0\end{array}\,\, \frac{\sin{(4\theta)}}{5\theta}}\)


This looks bad, but it works very much the same way:


. . . . .\(\displaystyle \large{\frac{\sin{(4\theta)}}{5\theta}\, =\,\left(\frac{4}{4}\right)\,\left(\frac{\sin{(4\theta)}}{5\theta}\right)\, =\,\left(\frac{4}{5}\right)\,\left(\frac{\sin{(4\theta)}}{4\theta}\right)}\)


Then you'd take the 4/5 out front, and evaluate according to the usual rule.
 
I think you will find, as you go through life, and become more aware of your surroundings, that humans manage to conceive of nearly every kind of evil. :evil: In fact, the capacity of humans to do evil may be without bound. :twisted:

...

What?

...

Oh, it's a MATH question! :eek:

...

Never mind. :oops:
 
Yes, the subject line could better have been written as "taking limits with sines". 8-)

Eliz.
 
I have a question how does everyone write the math work so neat on here for example everyone has sin x/ 3x written in the neater nice way how do u do that and how do u get square roots on here also Thanks [/quote]
 
At the top of the webpage there is a ‘Forum Help’ tab.
On that tab there are several links. Using TeX one can typeset mathematics
If you use Windows then TeXaide is a free LaTex editor.
 
Top