compute limit

limcos(3x)-1

x->0 sin(x)sin(x)

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- May 3rd 2009, 06:33 AMmanalive04limits problem
compute limit

lim__cos(3x)-1__

x->0 sin(x)sin(x) - May 3rd 2009, 06:42 AMRapha
- May 3rd 2009, 06:58 AMmanalive04
- May 3rd 2009, 07:13 AMRapha
Okay, it is

Therefor we use L'Hospital

We know that

Thus

=>

=>

=

=

Any questions? - May 3rd 2009, 07:42 AMmanalive04
how did you calculate the cos(3x) how is that broken down?

i know cos(2x) is cos(x)cos(x) - sin(x)sin(x)

but how did u do this one - May 3rd 2009, 07:48 AMHallsofIvy
- May 3rd 2009, 07:49 AMRapha
Hi again.

I'm glad you ask, but what exactly is the question?

Click here:

List of trigonometric identities - Wikipedia, the free encyclopedia

Use this formula for n=3

???

Does it help? - May 3rd 2009, 07:52 AMcurvature
Using l'Hospital's Rule