# Math Help - Limits of Trig Functions

1. ## Limits of Trig Functions

Can someone give me a quick lesson on solving for the limits of trig functions. my teacher didn't do a very good job of it, and she expects us to take a quiz after the first day. i'm in so much trouble, so if someone could help

2. This is a bit too vague I think. There's quite a lot of material I can think of that has to do with trig limits.

Here's a link that covers two important special limits, with some examples:

Special Trigonometric Limits - Library of Math

3. um, the teacher taught us the squeezing theorem, but said it wouldn't work everytime. the one i'm stuck on right now is:

limit x-->0 x^2/1-cos^2x

or

limit x--> positive infinity sin^-1(x/1-2x)

or

limiit x-->0 tan 3x^2 + sin^2 (5x) / x^2

4. #1) $\lim_{x \rightarrow 0} \frac{x^2}{1-\cos^2(x)}$. (1)

Use $\sin^2(x)+\cos^(x)=1$.

(1) = $\frac{x^2}{\sin^2(x)}= \left( \frac{x}{\sin(x)} \right) ^2= \left( \frac{\sin(x)}{x} \right) ^{-2}$

See where this is going?

5. so because sin x/x = 1.