Предмет: Математика, автор: owlj

cos2x+sinx=0
уравнение, срочно

Ответы

Автор ответа: Utem
0
cos2x+sinx=0
cos2x=cos²x-sin²x=1-2sin²x
1-2sin²x+sinx=0
Вводим замену переменной
sinx=t
-2t²+t²+1=0
D=1²-4*(-2)=1+8=9
t=(-1-3)/-4=1     t=(-1+3)/-4=-1/2
sinx=1               sinx=-1/2
x=π/2                x=7π/6
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