4 = X * Y
17 = 2 * ( X + Y) --> X + Y = 8.5 ---> X = 8.5 - Y
4 = Y*(8.5 - Y)
4 = 8.5Y - Y^2
-Y^2 + 8.5Y - 4 = 0
D = 72.25 - 4*(-1)*(-4) = 72.25 - 16 = 56.25 ; V D = 7.5
Y1 = ( - 8.5 + 7.5) : ( -2) = ( - 1) : ( - 2) = 0.5
Y2 = ( - 16 ) : ( -2 ) = 8
X = 8.5 - Y
X1 = 8.5 - Y1 = 8.5 -0.5 = 8
X2 = 8.5 - Y2 = 8.5 - 8 = 0.5
<span>Ответ: стороны прямоугольника 8 и 0.5 </span>
P(X) = { {1}, {3}, {6}, {7}, {1,3}, {1,6}, {1,7}, {3,6}, {3,7}, {6,7}, {1,3,6}, {1,3,7}, {3,6,7}, {1,6,7}, {1,3,6,7}, ∅ }
Sin4a+cos2a+cos2asin2a=sin4a+cos2a(1+sin2a)=sin4a+cos2a(sina+cosa)^=sin4a+cos2a=2sin2acos2a+cos2a=cos2a(2sina+1)=0
cos2a=0
2a=pi/2+pi n
a=pi/4+pi n/2
2sina+1=0
sina=-1/2
a=(-1)^n+1*pi/6