Question

Chứng minh rằng:

1/3² + 1/4² + 1/5² + 1/6² + ... + 1/100² < 1/2

Answer 1

Dat A=/3²+1/4²+1/5²+1/6²+...+1/100²<1/2.3+1/3.4+1/4.5+1/5.6+...+1/99.100                                                                 A<1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+...+1/99-1/100<1/2                                   Chung to...

Answer 2

=> 1/3²+1/4²+1/5²+ ....+ 1/100²<1/2.3+1/3.4+1/4.5+...+1/99.100

=> 1/3²+1/4²+1/5²+ ....+ 1/100²<1/2-1/100=49/100<1/2

=> 1/3²+1/4²+1/5²+ ....+ 1/100²<1/2 (đpcm)

                 ( k cho mình nha )