Suppose f(x) is continuous on [2,8] and −4≤f′(x)≤5 for all x in (2,8). use the mean value theorem to estimate f(8)−f(2).

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).