# Thread: Limits Involving Trigonometric Functions

1. ## Limits Involving Trigonometric Functions

I am reviewing for my midterm and realize that I was out sick when the class covered trigonometric functions. Any explanation on how to solve these would be great!
-limx->0 (x/arcsinx)
-limx->infinity (xarccotx)

2. Originally Posted by amm345
I am reviewing for my midterm and realize that I was out sick when the class covered trigonometric functions. Any explanation on how to solve these would be great!
-limx->0 (x/arcsinx)
-limx->infinity (xarccotx)
Hint:

$\frac{1}{f'(x)}$

and

Let $x=\frac{1}{z}$.

3. how about using L'Hospital's rule? that makes it a lot easier. by the way wats the answer.is the first one =1???

4. I thought the first one was 0? and I already tried L'Hopitals and I still couldn't figure out.

5. u need to differentiate the numerator and the denominator separately.then the numerator becomes 1.and the denominator becomes 1/sqrt(1-x^2).now put the limits and u should get 1.

6. How about when I can't do it seperately?
Like for limx->0 x/arccosx?

7. i donot get the second one. limit doesnot exist for the second one unless x->0.

8. x does tend to 0, isn't the limit equal to 0?

9. no. limit for the second one is also 1.provided ,ofcourse,if x->0.

10. u must learn your differentiation formulas well.