More trig shortcuts (PDF)

Watch free mathematics proofs videos at: www.youtube.com/mathsvideosforweb

For *ad free* mathematics proofs videos, visit: lbry.tv/$/invite/@mathsvideosforweb:9

For mathematical art, visit: www.instagram.com/tiago_hands/

For mathematical proofs, visit: www.instagram.com/mathematics.proofs/

To buy mathematics proofs books and A Level mathematics books, visit: www.amazon.co.uk/shop/mathematics.proofs