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The interval in which f(x)=x2+2xf(x) = \frac{x}{2} + \frac{2}{x} is a decreasing function of xx is :

Solution

✅ Correct Option: 3

f′(x)=12−2x2=x2−42x2f'(x) = \frac{1}{2} - \frac{2}{x^2} = \frac{x^2 - 4}{2x^2}. For decreasing, f′(x)<0⇒x2−4<0⇒−2<x<2f'(x) < 0 \Rightarrow x^2 - 4 < 0 \Rightarrow -2 < x < 2, x≠0x \neq 0. So decreasing on (−2,0)∪(0,2)(-2, 0) \cup (0, 2).

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