22●õ2+2õó+ó2–4
22●πk,k*Z |sin2x=2sinx|
22●πk, k*Z, arctg2+πn, n*Z |tg²x=2tgx|
22●4πn≤x≤2π+4πn, n*Z |y=2+√sin x/2|
22●õ=π/2+πn, n*Z | y=2x+sin2x |
22●a•b/2c (a•b/c)
22●–45î
22●x4–y4 {(x–y)(x+y)(x²+y²)
22●4 {(a/b+b/a)²–(a/b–b/a)²