Historical clue formulations

• Trigonometry ratio — 2025-11-18
• Trig function — 2023-04-30
• Trig function — 2019-03-03
• Secant's reciprocal — 2018-03-07
• Trig function — 2012-07-31
• 0, for 90 degrees — 2012-07-14
• Trig function — 2010-11-03
• Trig function — 2005-01-26
• Math function — 2003-10-04
• Trig function — 2002-04-30