In How Create Fishnet works from the ArcGIS Help it says:
Calculating a value for the y-axis coordinate If you know the angle of rotation, you can compute a value for the Y-Axis Coordinate parameter as follows: Tangent of angle = x-coordinate / y-coordinate Fishnet Y-Axis point calculation For example, the angle is 60 degrees. Assuming the y-coordinate to be 10, then x-coordinate = tan(60) * 10 = 1.732 * 10 = 17.32 The y-axis coordinate point is (17.32,10).
x-coordinate = (math.tan(math.radians(60) * 10) * 10) print x-coordinate >>>17.32
Perfect that's correct!
Now lets try using a real coordinate
Lat = 51.003757 Long, -114.09341083433694 or in NAD83 UTM Zone 11 x, y = 703919.581359, 5654264.1538 in UTM Zone 11
Using the same formula replacing 10 with the y-coordinate of the lat/long, and x,y of UTM as above none of the results make sense. What am I missing?