Watch video PreCalculus - Trigonometry: Trig Identities (5 of 57) Verify the Identity: 1 online without registration, duration 04 minute 08 second in high hd quality. This video was added by user Michel van Biezen 10 August 2014, don't forget to share it with your friends and acquaintances, it has been viewed on our site 15 thousand once and liked it 17 people.