Question

M​=1/2.2/3.3/4.4/5.......99/100 .Cmr 1/15<M<1/110

Answer 1

Lời giải:

$M=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{99}{100}$

$=\frac{1.2.3.4....99}{2.3.4...100}=\frac{1}{100}$

Hiển nhiên $\frac{1}{15}> \frac{1}{100}> \frac{1}{110}$ nên ta có đpcm.

Answer 2

** Sửa đề: CMR: $\frac{1}{15}> M> \frac{1}{110}$