Posted by **Michael** on Sunday, September 28, 2008 at 8:15pm.

We are doing limits in Calculus, but now we are doing trig limits too and i do not get how to do any of them.

For example ones like this, how do you do them?

sec (x-1) / (x sec x) x approaches 0

((3 sin (x)) 1 - cos(x)) / (x^2) x approaches 0

(sin (2x)) / (sin (3x)) x approaches 0

(1-tan(x)) / (sin (x) - cos (x)) x approaches 0

I just want to learn how to these kinds of limits so i know how to do all the types.

Please help, is there a website that will teach me how to do these kinds of limits?

Thank You.

- Calculus -
**drwls**, Sunday, September 28, 2008 at 8:28pm
If going to the limit results in a 0/0 or infinity/innfinity indeterminate fraction, then take the ratio of the derivatives of the numerator and denominator to get the limit. That is called L'Hopital's rule.

For the question

Lim (sin (2x)) / (sin (3x))

x->0

the answer is [2 (cos(0)]/[3 cos(0)] = 2/3

Remember that sin x is very close to x when x is small. this tells you right away that it approaches 2x/3x = 2/3

For a website that should help, Google "L'Hopital's rule".

One good site is

http://en.wikipedia.org/wiki/L'H%C3%B4pital's_rule

## Answer this Question

## Related Questions

- calculus (limits) - Use limits to explain why f(x)= (7-3X)/(X+9) has a vertical ...
- Maths Calculus Derivatives & Limits - Using the definition of the derivative ...
- Calculus - TWO examples of each of the following: two sided limits and theorem ...
- Math - I'm in Calculus AP and we are learning about limits. I'm having trouble ...
- Calculus - TWO examples of two sided limits and each theorem on limits.
- Calculus please help!!! double integral - Combine the following two integrals ...
- Calculus - Following 2 questions are from a book at a point where L’Hopital’s ...
- Calculus - Following 2 questions are from a book at a point where L’Hopital’s ...
- Calculus 1 - Write a function that has two infinite limits at two different x-...
- Calculus (Limits) - Let f be defined as follows, where a does not = 0, f(x) = {(...

More Related Questions