calculate Azimuth between tow points given in lat/long with VBA : Please i have to calculate the azimuth between tow points given in lat/long
but this function isn't correct

please can someone help me !!!!!
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Function azimut(lat1, lat2, lon1, lon2)

azimut = WorksheetFunction.Degrees(WorksheetFunction.Atan2(Cos(Application.WorksheetFunction.Radians(lat1)) * Sin(Application.WorksheetFunction.Radians(lat2)) - Sin(Application.WorksheetFunction.Radians(lat1)) * Cos(Application.WorksheetFunction.Radians(lat2)) * Cos(Application.WorksheetFunction.Radians(lon2 - lon1)), Sin(Application.WorksheetFunction.Radians(lon2 - lon1)) * Cos(Application.WorksheetFunction.Radians(lat2))))

End Function