Tính M/N biết M = 99/1 + 98/2 + 97/3 + ... + 2/98 + 1/99 và N = 1/2 + 1/3 + 1/4 +...+1/99+1/100
` (1/99 + 1/98 + 1/97 + ..... + 99/1)/(1/2 + 1/3 + 1/4 + ...... + 1/100)`
Bài 4: Tính tổng 1) 1 + (-2) + 3 + (-4) + . . . + 19 + (-20) 2) 1 – 2 + 3 – 4 + . . . + 99 – 100 3) 2 – 4 + 6 – 8 + . . . + 48 – 50 4) – 1 + 3 – 5 + 7 - . . . . + 97 – 99 5) 1 + 2 – 3 – 4 + ... + 97 + 98 – 99 - 100
(1/2+1/3+1/4+...+1/100):(99/1+98/2+97/3+...+1/99) =?
tinh tong gia tri bieu thuc :
a)A=1+1/3+1/5+...+1/97+1/99/1/1*99+1/3*97+1/5*95+...+1/97*3+1/99*1
b)B=1/2+1/3+1/4+...+1/100/99/1+98/2+97/3+...+1/99
tính tổng
1-2+3-4+....+99-100
-1+3-5+7-....-97+99
1+2-3-4+...+97+98-99-100
Rút gọn (1/99+2/98+3/97+...+99/1):(1/2+1/3+1/4+...+1/100)
C= 1/100 -1/100×99 -1/99×98 -1/98×97-...-1/3×2 - 1/2×1
Tính tổng
1/1-2+3-4+...+99-100
2/2-4+6-8+...+48-50
3/-1+3-5+7-...+97-99
4/1+2-3-4+...+97+98-99-100
