Սինուս, Կոսինուս

1-cos2a = sin2a
1/cos2a-1 = 1-cos2a/cos2a = sin2a/cos2a = tan2a
tgactga + ctg2a = 1 + ctg2a = 1/cos2a
tgbctgb + tg2b = 1 + tg2b = 1/sin2a
sin2a/cos2a + 1 = tga+1
1-cos2a = sin2a
1/cos2a-1 = 1-cos2a/cos2a = sin2a/cos2a = tan2a
tgactga + ctg2a = 1 + ctg2a = 1/cos2a
tgbctgb + tg2b = 1 + tg2b = 1/sin2a
sin2a/cos2a + 1 = tga+1