Inaccuracy of TAN near 75° in rad mode

[BarryMead]

Another way to say what Dieter is saying is that ANY function that has a STEEP slope, causes input errors to be AMPLIFIED on the output. The steeper the slope the greater the affect. The concept of accuracy is not absolute (to a certain number of digits) in situations like this. Even very tiny errors in the input to the function can generate very significant changes (NOT REALLY ERRORS) on the output.

Hope this helps to clear up the issue. Sincerely, Barry