Скачать или смотреть How to Prove Trigonometric Identities

This trigonometry lesson shows you how to prove intermediate problems on solving trigonometric identities. On solving trig identities, mastery of your algebra skills is a must. There are some techniques in simplifying trig identities which require to simplify rational expressions and even factoring trig expressions similar to some algebraic expressions.


00:42 sec x – tan x sin x = 1 / sec x
03:06 (1+cos x) / sin x = csc x + cot x
04:12 (sec x sin x) / (tan x + cot x) = sin^2 x
07:35 sec B / cos B – tan B / cot B = 1
11:23 cos^2y – sin^2y = 1 – 2sin^2y
12:34 csc^2 c tan^2x – 1 = tan^2 x
14:40 (tan x / sec x) + (cot x / csc x) = sin x + cos x
18:18 (sin x + cos x) (tan x + cot x) = sec x + csc x