Предмет: Математика, автор: xoxlov1992

вычислить ctga, если cosa=-1/2 и п/2

Ответы

Автор ответа: Amigo3

0

Так как диапазон углов не определён, то значения угла могут быть а1=120 и а2=240 градусов. sin(120)=0,5*√3, sin(240)=-0,5*√3. tg120= sin(120)/cos(120)=0,5*√3/(-0,5)=-√3. Для второго угла tg240= sin(240)/cos(240)=-0,5*√3/(-0,5)=√3.

Ответ: tg120= -√3; tg240= √3.

amin07am: Соs 150°=cos (90°+60°)=-sin 60°=-1/2 (кв.корень 3).

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