An xyz-coordinate system is placed with its origin at the center of the earth, so that

Question

the equator is in the xy-plane, the North Pole has coordinates (0, 0, 3960), and the xz-plane
contains the prime meridian, which is the great semicircle that runs through Greenwich,
England on its way from the North Pole to the South Pole. Recall that the y-axis is oriented
so that it points east, into the Indian Ocean. Find the coordinates (x, y, z) of Exeter NH,
whose latitude and longitude are 43 degrees north and 71 degrees west.

Answer 1

the point (r,lat,long) is at (r cos(long) sin(lat),r sin(long) sin(lat),r cos(lat))