I derive the exact value for Tan(18 degrees) using the half angle formula.
Sorry James Elliott! I forgot your name.
But here's the video:
https://youtu.be/UMO2UrAedbc
https://owlsmath.neocities.org
https://owlsmath.neocities.org/Trig%20Identities%20and%20Formulas/trig%20identities.html
