Posted by **jane** on Monday, November 3, 2008 at 10:10pm.

Help

Have some more that I do not understand.

Limit theta approaching zero

SinTheta minus Tan theta/ sin cubed theta

- HS Calculus -
**drwls**, Tuesday, November 4, 2008 at 9:48am
Rewrite as [sin x(1 - 1/cosx)]/sin^3x

= [1 - (1/cosx)]/[1 - cos^2x]

Now use L'Hopital's rule and take the ratio of the derivatives of numerator and denominator. That lets you get rid of the 1's.

You are left with

Lim [-tanx secx/(2cosx sinx)]

= Lim -1/(2 cos^3x)

Which is -1/2

- HS Calculus -
**drwls**, Tuesday, November 4, 2008 at 12:05pm
It took me a while to get that one. I cheated and used a hand calculator first, and it agrees.

## Answer this Question

## Related Questions

- HS Calculus - Have some more that I do not understand. Limit theta approaching ...
- HS Calculus - 1) Limit theta approaching zero sin squared theta/ tan theta 2) ...
- HS Calculus - 1) Limit theta approaching zero sin squared theta/ tan theta 2) ...
- Calculus - I wanted to confirm that I solved these problems correctly (we had to...
- Maths- complex numbers - Find tan(3 theta) in terms of tan theta Use the formula...
- math - I have a question I have been working on since yesterday and I am not ...
- Calculus - Below are the 5 problems which I had trouble in. I can't seem to get ...
- Algebra II - Multiple Choice Which expression is NOT equivalent to 1? (theta) ...
- trig - If sin theta is equal to 5/13 and theta is an angle in quadrant II find ...
- science - Sitting on a horizontal track is a mass of 10kg. One end of the track ...

More Related Questions