Watch video PreCalculus - Trigonometry: Trig Identities (7 of 57) Verify the Identity: 3 online without registration, duration 02 minute 58 second in high hd quality. This video was added by user Michel van Biezen 05 August 2014, don't forget to share it with your friends and acquaintances, it has been viewed on our site 6 thousand once and liked it 9 people.