On-line Math 21

On-line Math 21

3.1  Trigonometric functions

3.1.1  Limits of trig functions

In order to understand the calculus of sin(x) , or any trigonometric function, we first need to find some limits involving trigonometric functions. First, we deal with the limit

lim
x® 0 
 sin(x)
x
 .

To apply the squeeze principle to this situation, we need to look for functions on either side, to compare it to. The picture below shows what we need.

The area of the other triangle, OBD , is
1
2
 tan(q),
since it is a right triangle with base 1 and height tan(q) , which you can see by turning the picture upside down.

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Copyright (c) 2000 by David L. Johnson.

File translated from TEX by TTH, version 2.61.
On 28 Nov 2000, 16:49.