Historical clue formulations

• Not the main point — 2023-06-14
• 1, for 45° — 2017-12-07
• Trig calculation — 2015-11-08
• Digression — 2014-08-09
• Trigonometric function — 2005-02-15
• See 57-Across — 2000-05-14
• It doesn't go in circles — 1995-06-23