Telephone calls reach a secretary independently and at random ,internal ones at a mean rate of 2 in any five minute period and external ones at a mean rate of 1 in any five minute period . Calculate the probability that there is more than 2 calls in any period of 2 minutes

1. what is the formula for finding the vertical distance between two points on a coordinate plane?

The system of equations graphed below has how many solutions? y = 2x + 2

Find a parametrization for the curve「and determine the work done on a particle moving along γ in r3 through the force field f: r^3--r^3'where f(x, y,z) = (1,-x, z) and (a) im (γ) is the line segment from (0,0,0) to (1,2,1) (b) im (γ) is the polygonal curve with successive vertices (1,0,0), (0,1,1), and (2,2,2) (c) im (γ) is the unit circle in the plane z = 1 with center (0,0,1) beginning and ending at (1,0,1), and starting towards (0,1,1)