A plane is flying at an elevation of 35,000 feet when the Gateway Arch in St. Louis, Missouri comes into view. The pilot wants to estimate her horizontal distance from the arch, so she notes the angle of depression, \( \theta \), between the horizontal and a line joining her eye to a point on the ground directly below the arch, Make a sketch. Express her horizontal distance to the arch as a function of \( \theta \).

5th Ed: #35