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D( x )
x = 0
x*x = 0
x = 0
x = 0
x*x = 0
x*x = 0
1*x^2 = 0 // : 1
x^2 = 0
x = 0
x in (-oo:0) U (0:+oo)
1/x+2/x+3+4 = 7*x-1/(x*x)+12 // - 7*x-1/(x*x)+12
1/x-(7*x)+2/x-(-1/(x*x))-12+3+4 = 0
1/x-7*x+2/x+x^-2-12+3+4 = 0
3*x^-1-7*x^1+1*x^-2-5*x^0 = 0
(3*x^1-7*x^3-5*x^2+1*x^0)/(x^2) = 0 // * x^4
x^2*(3*x^1-7*x^3-5*x^2+1*x^0) = 0
x^2
3*x-7*x^3-5*x^2+1 = 0
{ 1, -1 }
1
x = 1
3*x-7*x^3-5*x^2+1 = -8
1
-1
x = -1
3*x-7*x^3-5*x^2+1 = 0
-1
x+1
2*x-7*x^2+1
3*x-7*x^3-5*x^2+1
x+1
7*x^3+7*x^2
2*x^2+3*x+1
-2*x^2-2*x
x+1
-x-1
0
2*x-7*x^2+1 = 0
DELTA = 2^2-(-7*1*4)
DELTA = 32
DELTA > 0
x = (32^(1/2)-2)/(-7*2) or x = (-32^(1/2)-2)/(-7*2)
x = (4*2^(1/2)-2)/(-14) or x = (-4*2^(1/2)-2)/(-14)
x in { (4*2^(1/2)-2)/(-14), (-4*2^(1/2)-2)/(-14), -1}
x in { (4*2^(1/2)-2)/(-14), (-4*2^(1/2)-2)/(-14), -1 }
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