### Searching for trigonometric identity proofs?

#### Here you can watch videos and download files that will teach you how to derive the most popular trigonometric formulas from absolute scratch.

*Take your pick!*

A proof related to this identity [sin(A+B)] can be found here: https://www.youtube.com/watch?v=4K6xr8hjkTw&index=2&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK

A proof related to this identity [sin(A-B)] can be found here: https://www.youtube.com/watch?v=sTOnQK7NfD0&index=3&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK

A proof related to this identity [cos(A+B)] can be found here: https://www.youtube.com/watch?v=-n6h6-CT0-0&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK&index=4

A proof related to this identity [cos(A-B)] can be found here: https://www.youtube.com/watch?v=gDOGT6NcD60&index=5&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK

A proof related to this identity [tan(A+B)] can be found here: https://www.youtube.com/watch?v=enSr4H1uCA4&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK&index=6

A proof related to this identity [tan(A-B)] can be found here: https://www.youtube.com/watch?v=SOkmA38B9kc&list=PLFM03zQeSz2MVj_4R9SZifMTL0re19LhK&index=7

Proofs related to these trigonometric identities can be found here: http://mathsvideos.net/free-resources-downloads/

Just search for the zip file titled “trig_proofs_sept_16”. The file’s URL is: http://mathsvideos.net/wp-content/uploads/2015/02/trig_proofs_sept_16.zip

**Trigonometric identity Youtube playlist:**

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