significant digits

Questions
,
1

how do I get more significant digits for this result?

http://www.wolframalpha.com/input/?i=a%3D.999%2C+b%3D1%2C+%28arctan%28a%29-arctan%28b%29%29%2F%28a-b%29

2

Don’t use decimal points

http://www.wolframalpha.com/input/?i=%28arctan%28999%2F1000%29-arctan%281%29%29%2F%28999%2F1000-1%29

3

thanks

works with the a and b substitution too:

http://www.wolframalpha.com/input/?i=a%3D999%2F1000%2C+b%3D1%2C+%28arctan%28a%29-arctan%28b%29%29%2F%28a-b%29

4

found that you can also get more precision by keeping the decimal point and adding a bunch of zeros:

http://www.wolframalpha.com/input/?i=a%3D.999000000000000000000000000000%2C+b%3D1%2C+%28arctan%28a%29-arctan%28b%29%29%2F%28a-b%29

5

I learned something from your posting. Thank you.

I thought from previous experiments that WolframAlpha didn’t understand assignments to variables.
Perhaps I was wrong or perhaps this is something new that has been added.

If it is new then I wonder if there is a page where new features are announced?