 Limit of a function properties (theorems or laws)

Composition rule
Limits of functions properties use, examples
Limit properties
 Assume that exist and that c is any constant. Then,  11.   Squeeze rule
If   f(x) < g(x) < h(x)  for all x in an open interval that contains a, except possibly at x = a
 and then 12.  Composition rule
 If   f(x) is continuous at x = b and then, Limits of functions properties use examples
Limits that are commonly used are written below for easy reference, By comparing the area of the sector of the arc x with
areas of the two right triangles, the smaller triangle
with legs sin x and cos x, and the bigger triangle with
legs tan x and 1, shown on the right figure, we get Since the left and the right side of the last inequality
tend to the same limit 1, as x tends to 0 then,
applying the squeeze rule obtained is  the fundamental or basic trigonometric limit. Note that the arc length x is measured in radians.
Further, since both factors on the right tend to 1, as x tends to 0, then    Functions contents E 