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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def change_in_longitude(lat, miles):
 """Given a latitude and a distance west, return the change in longitude."""


    # Find the radius of a circle around the earth at given latitude.
    r = earth_radius * math.cos(lat * degrees_to_radians)
    return (miles / r) * radians_to_degrees