B=1.3+2.4+3.5+...+97.99+98.100
B=1(2+1)+2(3+1)+....+97(98+1)+98(99+1)
B=1.2+1+2.3+2+....+97.98+97+98.99+98
B=(1.2+2.3+3.4+....+97.98+98.99)+(1+2+3+...+98)
B=98.99.100/3 + 98.99/2
B=323400+4851=328251
1.3 + 2.4 + 3.5 + 4.6 +.........+ 97.99 + 98.100
1/1.3-1/2.4+1/3.5-1/4.6+...+1/97.99-1/98.100 = ?
TÍNH: a. \(1.3+3.5+....+97.99\)
b.\(1.3+2.4+3.5+....+98.100\)
c.\(2.4+4.6+....+98.100\)
chứng minh rằng:1/1.3 + 1/2.4 + 1/3.5 + 1/4.6 +....+ 1/97.99 + 1/98.100 < 3/4
chứng minh rằng 1^1.3 + 1^2.4 + 1^3.5 + 1^4.6 +...+ 1^97.99+ 1^98.100 < 3^4
Tính 1.3+2.4+3.5+...+97.99+98.100
tính nhanh:1.3+2.4+3.5+.....+97.99+98.100
tính 2.4+3.5+4.6+5.7+6.8+7.9+8.10+...+97.99+98.100
1.3+2.4+3.5+...+97.99+98.100
