$$\frac{7x}{(-2x^2+4)^{\frac{1}{2}}}$$ isn't a real number. What's the range of x?
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A$$- \sqrt{2} \leq x \leq \sqrt{2}$$
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B$$x \geq \sqrt{2}$$ or $$x \leq -\sqrt{2}$$
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C$$-2 \leq x \leq 2$$
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D$$x \geq 2$$ or $$x \leq -2$$
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E$$x \geq \sqrt{3} $$ or $$x \leq -\sqrt{3}$$
显示答案
正确答案: B