Toán Lớp 5: tính nhanh: ( 1 + 1/3 ) : (1 + 1/4 ) : (1 + 1/5 ) : -.: ( 1 + 1/2021)

Question

Toán Lớp 5:  tính nhanh: ( 1 + 1/3 ) : (1 + 1/4 ) : (1 + 1/5 ) : .....: ( 1 + 1/2021)

kimoanh34 · Answer

A    =     (     1    +       1      2        )      (     1    +       1      3        )      (     1    +       1      4        )     .    .    .     (     1    +       1      2021        )      A=(1+12)(1+13)(1+14)...(1+12021)             =       3      2       &sdot;       4      3       &sdot;       5      4       &sdot;    .    .    .    &sdot;       2022      2021        =32&sdot;43&sdot;54&sdot;...&sdot;20222021             =       2022      2        =20222             =    1011

lyly98 · Answer

đặt    A=(1+12)(1+13)(1+14)...(1+12021)  A         t/c&oacute;: A=(1+12)(1+13)(1+14)...(1+12021)          =(1+12)(1+13)(1+14)...(1+12021)          =32&sdot;43&sdot;54&sdot;...&sdot;20222021  =32&sdot;43&sdot;54&sdot;...&sdot;20222021          =20222/20222         =1