Đặt A = 1/3.5 + 1/5.7 + 1/7.9 + ..... + 1/99.101
=> 2A = 2/3.5 + 2/5.7 + 2/7.9 + ..... + 2/99.101
=> 2A = 1/3 - 1/5 + 1/5 - 1/7 + ..... + 1/99 - 1/101
=> 2A = 1/3 - 1/101
=> 2A = 88/303
=> A = 44/303
1/3x5 + 1/5x7 + 1/7x9 +...+ 1/99x101
Tính
a. 3/(3x5) + 3/(5x7) + 3/(7x9) +... + 3/(99x101)
b. 5/(3x5) +5/(5x7) +5/(7x9) +...+ 5/(99x101)
Bài 1 Tính
a) A=1/2x3+1/3x4+1/4x5+1/5x6+...+1/99x100
b) B=2/3x5+2/5x7+2/7x9+...+2/99x101
c) C=3/3x5+3/5x7+3/7x9+...+3/99x101
d) D=4/3x8+4/8x13+4/13x8+...+4/53x58
Các bạn làm hộ giúp mình với cho mình lời giải
1x3/3x5 + 2x4/5x7 + 3x5/7x9 + ............... +49x51/99x101
1x3/3x5 + 2x3/5x7 + 3x5/7x9 + ............... +49x51/99x101
1/1x5+1/5x7+1/7x9+...+1/99x101 = ?
bieu thuc 4/3x5+4/5x7+4/7x9=..........................+4/97x99+4/99x101 có gia trị là bao nhiêu ?
1/1x3+1/3x5+1/5x7+.......+1/99x101
1/1x3 + 1/3x5 + 1/5x7 + 1/7x9