Question

20£®¹Û²ìÏÂÁÐʽ×Ó£º¢Ù$\sqrt{2-\frac{2}{5}}=2\sqrt{\frac{2}{5}}$£»¢Ú$\sqrt{3-\frac{3}{10}}=3\sqrt{\frac{3}{10}}$£»¢Û$\sqrt{4-\frac{4}{17}}=4\sqrt{\frac{4}{17}}$£»¢Ü$\sqrt{5-\frac{5}{26}}=5\sqrt{\frac{5}{26}}$£»¡­ÇëÄã°´ÕÕ¹æÂÉд³öµÚn£¨n¡Ý1£©¸öʽ×ÓÊÇ£¨¡¡¡¡£©

• A£® $\sqrt{n-1-\frac{n-1}{£¨n-1£©^{2}+1}}$=£¨n-1£©$\sqrt{\frac{n-1}{£¨n-1£©^{2}+1}}$
• B£® $\sqrt{n-\frac{n}{{n}^{2}-1}}=n\sqrt{\frac{n}{{n}^{2}-1}}$
• C£® $\sqrt{n+1-\frac{n+1}{£¨n+1£©^{2}+1}}$=£¨n+1£©$\sqrt{\frac{n+1}{£¨n+1£©^{2}+1}}$
• D£® $\sqrt{n-\frac{n}{{n}^{2}+1}}=n\sqrt{\frac{n}{{n}^{2}+1}}$

Answer 1

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