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D( x )
x^4+81 = 0
x^4+81 = 0
x^4+81 = 0
1*x^4 = -81 // : 1
x^4 = -81
x in (-oo:+oo)
(18*x^2)/(x^4+81)-1 = 0
(18*x^2)/(x^4+81)+(-1*(x^4+81))/(x^4+81) = 0
18*x^2-1*(x^4+81) = 0
18*x^2-x^4-81 = 0
18*x^2-x^4-81 = 0
18*x^2-x^4-81 = 0
{ 1, -1, 3, -3, 9, -9, 27, -27, 81, -81 }
1
x = 1
18*x^2-x^4-81 = -64
1
-1
x = -1
18*x^2-x^4-81 = -64
-1
3
x = 3
18*x^2-x^4-81 = 0
3
x-3
9*x-x^3-3*x^2+27
18*x^2-x^4-81
x-3
x^4-3*x^3
18*x^2-3*x^3-81
3*x^3-9*x^2
9*x^2-81
27*x-9*x^2
27*x-81
81-27*x
0
9*x-x^3-3*x^2+27 = 0
{ 1, -1, 3, -3, 9, -9, 27, -27 }
1
x = 1
9*x-x^3-3*x^2+27 = 32
1
-1
x = -1
9*x-x^3-3*x^2+27 = 16
-1
3
x = 3
9*x-x^3-3*x^2+27 = 0
3
x-3
-x^2-6*x-9
9*x-x^3-3*x^2+27
x-3
x^3-3*x^2
9*x-6*x^2+27
6*x^2-18*x
27-9*x
9*x-27
0
-x^2-6*x-9 = 0
DELTA = (-6)^2-(-9*(-1)*4)
DELTA = 0
x = 6/(-1*2)
x = -3 or x = -3
x in { -3, -3, 3, 3}
(x+3)^2*(x-3)^2 = 0
((x+3)^2*(x-3)^2)/(x^4+81) = 0
((x+3)^2*(x-3)^2)/(x^4+81) = 0 // * x^4+81
(x+3)^2*(x-3)^2 = 0
( x+3 )
x+3 = 0 // - 3
x = -3
( x-3 )
x-3 = 0 // + 3
x = 3
x in { -3, -3, 3, 3 }
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