Ответы: 2
АЛЁНА РУДЫК
2017-09-30 13:43
Ctga(1 — Cos2a) + Cos2a = Cosa/Sina(Sina + Cosa — Cosa + Sina) + + Cos2a = Cosa/Sina(2Sina) + Cos2a = Cosa/Sina * 4Sin^4a + Cos2a = = 4SinaCosa + ( 2Cosa — 1) = 4SinaCosa + 4Cos^4a — 4Cosa + 1 = = (4SinaCosa + 4Cos^4a) — 4Cosa + 1 = 4Cosa(Sina+ Cosa) — 4Cosa + 1 =4 Cosa — 4Cosa + 1 = 1

Даня Васильчук
2017-09-30 05:34
СtgA*(1-cos2A)+cosA=cosA/sinA *(2sinA)+cosA=cosA/sinA *4sin^4a+cos2A=4cosA*sinA+cos2A=sin2A+cos2A=1