A=1x3 +3x5 +5x7 +....+99x101
6A=1x3x(5+1) + 3x5x(7-1) +5x7x(9-3) +...+ 99x101x(103-97)
6A=3+ 1x3x5 +3x5x7-1x3x5 + 5x7x9 -3x5x7 +....+99x101x103 - 97x99x101
6A=3+99x101x103=1019703
1x3+3x5+5x7+...+99x101
tinh E=1x3+3x5+5x7+...+97x99+99x101
tinh E= 1x3+3x5+5x7+....+97x99+99x101
2\1x3+2\3x5+2\5x7+...+2\99x101
A=2/1x3+2/3x5+2/5x7+....+2/99x101
Tính bằng cách thuận tiện.
C= 1x3+3x5+5x7+...+99x101 giả thích vì sao là ?C
1/1x3+1/3X5+1/5X7+1/7X9+…+1/99X101
Cho S=1/1x3+1/3x5+1/5x7+..................1/99x101
Khi đó 2S+ 1/101=...................
M
chứng tỏ rằng :2/1x3+2/3x5+2/5x7+...+2/99x101<1
MIK ĐANG CẦN ĐÁP ÁN GẤP
