* = x
7m^4 - 9m²n + n² - 3m^4 - 6m²n = x
4m^4 - 15m²n + n² = x
А) (m¼ - n½)² - (m¼ + n½)²=m^1/2-2(mn)^1/4+n^1/2+m^1/2+2(mn)^1/4+n^1/2=
=2√m+2√n<span>
б) (m⅓ + 3n½)² + (m⅓ - 3n½)²=
=m^2/3+6m^1/3n^1/2+9n+</span>m^2/3-6m^1/3n^1/2+9n=2∛m²+18n<span>
в) (m½ - 2n¼) (m½ + 2n¼)=m-4</span>√n<span>
г) (m½ - 3n) (m + 3m½n + 9n²)=m^3/2-27n</span>³=√m³-27n³
Cos(a)cos(b)-sin(a)sin(b)+2sin(a)sin(b)
cos(a-b)
cos(a)cos(b)+sin(a)sin(b)
cos(a-b)
cos(a-b)
cos(a-b)=1
( X^3 + 5X^2) - ( 25X + 125 ) = 0
X^2 * ( X + 5) - 25 * ( X + 5 ) = 0
( X^2 - 25) * ( X + 5 ) = 0
( X - 5)*( X + 5)*( X + 5 ) = 0
=====================
X - 5 = 0
X = 5
============
X + 5 = 0
X = ( - 5 )
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Ответ плюс 5 и минус 5
По формуле:
cos(6x-5x)=-1
cos(x)=-1
x=Pi + 2*Pi*n, n принадлежит Z (множеству целых чисел).