Предмет: Математика, автор: tyugashkin2015

Решите мне пример
5-2sin²X+7cosX=0

Ответы

Автор ответа: shevtsovavalia

0

5-2(1-cos²x)+7cosx=0
2cos²x+7cosx+3=0
cosx=a
2a²+7a+3=0
D=25
a=-3; a=-1/2
cosx=-1/2
x=+-2π/3+2πn

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