Задача 14638 (cos a*tg a)^2+(sin a ctga)^2 ...

u294208183

01.04.2017

(cos a*tg a)^2+(sin a ctga)^2

SOVA

01.04.2017

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tgα=sinα/cosα
cosα*tgα=sinα

ctgα=cosα/sinα
sinα*ctgα=cosα

(cos α·tg α)^2+(sin α*ctgα)^2=sin^2α+cos^2α=1