TÍNH TỔNG S=1/5x6+1/10x9+1/15x12+.....+1/3350x2013
Tính hợp lý:(1+2+3+4+5+.......+2046)x(13x15-15x12-15)
1/10x9+1/18x13+1/26x17+...+1/802x405
tính nhanh 1x 5x6+2x10x12+x4x20x24+9x45x54
1x3x5+2x6x10+4x20x12+9x27x45
Áp dụng công thức tính S = 1x2+2x3+3x4+4x5+5x6+.....+nx(n+1)
tính : 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6
Tính:
(1/51+1/52+1/53+...+1/100):(1/1x2+1/3x4+1/5x6+...+1/99x100)
Tính nhanh :
1/4x5 + 1/5x6 + 1/5x7 +... + 1/15x16
giúp tui vs.
Tính :
a) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.....+1
b)1/1x2x3+1/2x3x4+1/3x4x5+.....+1/98x99x100
Tính :
a) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.....+1
b)1/1x2x3+1/2x3x4+1/3x4x5+.....+1/98x99x100
