Suppose we want to choose 3

colors, without replacement, from the 4

colors red, blue, green, and purple.

(a) How many ways can this be done, if the order of the choices is relevant?

(b) How many ways can this be done, if the order of the choices is not relevant?

What is the smallest integer n such that n\sqrt{2} is greater than 20

If value of cos330° is √3/2 then find tan165°.

On traditional maps, earth is represented in a flat plane, or by euclidean geometry. however, a globe is a more accurate model that comes from elliptical geometry.how does a globe represent the fact that there are no parallel lines in elliptical geometry? the equator is not parallel to any other latitudinal lines. the north and south poles are never connected by a geodesic. the geodesics connecting the north and south poles never intersect. the geodesics connecting the north and south poles intersect at both of the poles.