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D( x )
4-x^2 = 0
(4-x^2)^-0.5 = 0
4-x^2 < 0
4-x^2 = 0
4-x^2 = 0
-1*x^2 = -4 // : -1
x^2 = 4
x^2 = 4 // ^ 1/2
abs(x) = 2
x = 2 or x = -2
(4-x^2)^-0.5 = 0
(4-x^2)^-0.5 = 0
1/((4-x^2)^0.5) = 0
4-x^2 < 0
4-x^2 < 0
-1*x^2 < -4
-1*x^2 < -4 // * -1
1*x^2 > 4
1*x^2 > 4 // : 1
x^2 > 4/1
x^2 > 4
x^2 > 4 // ^ 1/2
abs(x) > 2
x in (-oo:-2) U (2:+oo)
x in (-2:2)
x/((4-x^2)^-0.5) = 0
x*(4-x^2)^0.5 = 0
( 4-x^2 )
-1*x^2 = -4 // : -1
x^2 = 4
x^2 = 4 // ^ 1/2
abs(x) = 2
x = 2 or x = -2
( x )
x = 0
x in { 2}
x in { -2}
x = 0
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