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D( r )
r^2 = 0
r^2 = 0
r^2 = 0
1*r^2 = 0 // : 1
r^2 = 0
r = 0
r in (-oo:0) U (0:+oo)
4/(r^2)-(2*r)-(2*r)-(12/(r^2))-3-3 = 0
4/(r^2)-2*r-2*r-12*r^-2-3-3 = 0
-4*r^1-8*r^-2-6*r^0 = 0
(-4*r^3-6*r^2-8*r^0)/(r^2) = 0 // * r^4
r^2*(-4*r^3-6*r^2-8*r^0) = 0
r^2
-4*r^3-6*r^2-8 = 0
{ 1, -1, 2, -2, 4, -4, 8, -8 }
1
r = 1
-4*r^3-6*r^2-8 = -18
1
-1
r = -1
-4*r^3-6*r^2-8 = -10
-1
2
r = 2
-4*r^3-6*r^2-8 = -64
2
-2
r = -2
-4*r^3-6*r^2-8 = 0
-2
r+2
2*r-4*r^2-4
-4*r^3-6*r^2-8
r+2
4*r^3+8*r^2
2*r^2-8
-2*r^2-4*r
-4*r-8
4*r+8
0
2*r-4*r^2-4 = 0
DELTA = 2^2-(-4*(-4)*4)
DELTA = -60
DELTA < 0
r in { -2}
r = -2
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