Earth has been charted with vertical and horizontal lines so that points can be named with coordinates. the horizontal lines are called latitude lines. the equator is latitude line 0. parallel lines are numbered up to pi/2 to the north and to the south. if we assume earth is spherical, the length of any parallel of latitude is equal to the circumference of a great circle of earth times the cosine of the latitude angle. a. the radius of earth is about 6400 kilometers. find the circumference of a great circle. b. write an equation for the circumference of any latitude circle with angle 0 c. which latitude circle has a circumference of about 3593 kilometers? d. what is the circumference of the equator?

Step-by-step explanation:

a) Circumference of great circle = 3.14r^2

= 6400(6400) 3.14= 128614400 km.

b) When angle =0 circumference =

pir^2cos 0

= 128614400 km since cos 0 = 1

c) When 3593 = 128614400 cos t

i.e. cost = 89.998

The circle around latitude which angle makes 89.998 with horizontal axis.

d) Circumference of equator = circum. of greater circle = 128614400 km

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1

i honestly dont know