Cos x - Sin x = Cos x - Cos(π/2 - x) =
= - 2Sinπ/4 * Sin(x-π/4) = -√2Sin(x-π/4)
X^2 = 49 / : V
x = 7 i x= - 7
x^2 = 10 /:V
x = V10 i x = - V10
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2sinx=sin2x
2sinx=2sinxcosx
2sinx(cosx-1)=0
sinx=0 cosx=1
x=(Пи)n x=2(Пи)n, n принадлежит Z
Ответ: x=(Пи)n, n принадлежит Z
1) (а-12)³ - 125=(a-12)³-5³=(a-12-5)((a-12)²+(a-12)*5+5²)=
=(a-17)(a²-24a+144+5a-60+25)=
=(a-17)(a²-19a+109)
2)(b+4)³+64=(b+4)³+4³=(b+3+4)((b+3)²+(b+3)*4+4²)=
=(b+7)(b²+6b+9+4b+12+16)=
=(b+7)(b²+10b+37)
3)81-(с²+6с)²=9²-(c²+6c)²=(9+c²+6c)(9-c²-6c)=(c+3)²(9-c²-6c)
<span>4)16m</span>²<span>-(m-n)</span>²=(4m)²-(m-n)²=(4m+m-n)(4m-m+n)=(5m-n)(3m+n)