Qo‘shish formulalari
Javoblar ota-onalar va o‘qituvchilar uchun.
1
sin 15° = sin(45° − 30°) ni hisoblang.
(√6 − √2)/4
2
cos 15° cos 75° − sin 15° sin 75° ni hisoblang.
0
3
sin α = 5/13, cos β = 3/5 (ikkala burchak I chorakda) bo‘lsa, sin(α + β) ni toping.
63/65
4
tg α = 2, tg β = 3 bo‘lsa, tg(α + β) ni toping.
−1
5
sin(α + β) + sin(α − β) = 2 sin α cos β ekanini isbotlang.
(sin α cos β + cos α sin β) + (sin α cos β − cos α sin β) = 2 sin α cos β.