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D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
1/x = 1.86257128811507 // - 1.86257128811507
1/x-1.86257128811507 = 0
1*x^-1 = 1.86257128811507 // : 1
x^-1 = 1.86257128811507
-1 < 0
1/(x^1) = 1.86257128811507 // * x^1
1 = 1.86257128811507*x^1 // : 1.86257128811507
0.5368922 = x^1
x = 0.5368922
x = 0.5368922
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