sin2x + cos2x = 1
tgx ctgx = 1
sin2x = 2sinx cosx
cos2x = cos2x - sin2x = 2cos2x - 1 = 1 - 2sin2x
sin3x = 3sinx - 4sin3xcos3x = 4cos3x - 3cosx
sin(α + β) = sinα cosβ + cosα sinβcos(α + β) = cosα cosβ - sinα sinβ
sin(α - β) = sinα cosβ - cosα sinβcos(α - β) = cosα cosβ + sinα sinβ
(sinα + cosα)2 = 1 + sin2α
(sinα - cosα)2 = 1 - sin2α
sin2x + cos2x = 1
tgx = sinxcosxctgx = cosxsinxtgx ctgx = 1
tg2x + 1 = 1cos2xctg2x + 1 = 1sin2xsin2x = 2sinx cosx
sin2x = 2tgx = 2ctgx = 21 + tg2x1 + ctg2xtgx + ctgxcos2x = cos2x - sin2x = 2cos2x - 1 = 1 - 2sin2x
cos2x = 1 - tg2x = ctg2x - 1 = ctgx - tgx1 + tg2xctg2x + 1ctgx + tgxtg2x = 2tgx = 2ctgx = 21 - tg2xctg2x - 1ctgx - tgxctg2x = ctg2x - 1 = ctgx - tgx2ctgx2Формулы тройного аргументаsin3x = 3sinx - 4sin3x
tg3x = 3tgx - tg3x1 - 3tg2xctg3x = ctg3x - 3ctgx3ctg2x - 1Формулы половинного аргументаsin2x = 1 - cosx22cos2x = 1 + cosx22tg2x = 1 - cosx21 + cosxctg2x = 1 + cosx21 - cosxtgx = 1 - cosx = sinx2sinx1 + cosxctgx = 1 + cosx = sinx2sinx1 - cosxФормулы квадратов тригонометрических функцийsin2x = 1 - cos2x2cos2x = 1 + cos2x2tg2x = 1 - cos2x1 + cos2xctg2x = 1 + cos2x1 - cos2xsin2x = 1 - cosx22cos2x = 1 + cosx22tg2x = 1 - cosx21 + cosxctg2x = 1 + cosx21 - cosxcos3x = 4cos3x - 3cosx
sin3x = 3sinx - sin3x4cos3x = 3cosx + cos3x4tg3x = 3sinx - sin3x3cosx + cos3xctg3x = 3cosx + cos3x3sinx - sin3xФормулы тригонометрических функций в четвертой степениsin4x = 3 - 4cos2x + cos4x8cos4x = 3 + 4cos2x + cos4x8
sin(α + β) = sinα cosβ + cosα sinβ
tg(α + β) = tgα + tgβ1 - tgα tgβctg(α + β) = ctgα ctgβ - 1ctgα + ctgβcos(α + β) = cosα cosβ - sinα sinβ
sin(α - β) = sinα cosβ - cosα sinβ
tg(α - β) = tgα - tgβ1 + tgα tgβctg(α - β) = ctgα ctgβ + 1ctgα - ctgβcos(α - β) = cosα cosβ + sinα sinβ
+ sinβ = 2sinα + β ∙ cosα - β22cosα + cosβ = 2cosα + β ∙ cosα - β22
(sinα + cosα)2 = 1 + sin2α
tgα + tgβ = sin(α + β)cosα cosβctgα + ctgβ = sin(α + β)sinα sinβФормулы разности тригонометрических функцийsinα - sinβ = 2sinα - β ∙ cosα + β22cosα - cosβ = -2sinα + β ∙ sinα - β22(sinα - cosα)2 = 1 - sin2α
tgα - tgβ = sin(α - β)cosα cosβctgα - ctgβ = – sin(α - β)sinα sinβsinα ∙ sinβ = cos(α - β) - cos(α + β)2sinα ∙ cosβ = sin(α - β) + sin(α + β)2cosα ∙ cosβ = cos(α - β) + cos(α + β)2tgα ∙ tgβ = cos(α - β) - cos(α + β) = tgα + tgβcos(α - β) + cos(α + β)ctgα + ctgβctgα ∙ ctgβ = cos(α - β) + cos(α + β) = ctgα + ctgβcos(α - β) - cos(α + β)tgα + tgβtgα ∙ ctgβ = sin(α - β) + sin(α + β)sin(α + β) - sin(α - β)