Cho M = 5/2.4 + 5/4.6 + 5/6.8 + ... + 5/ 96.98 + 5/98.100 . Tìm x.M-1=20/29
tính nhanh
\(Q=\frac{5}{2.4}+\frac{5}{4.6}+\frac{5}{6.8}+...+\frac{5}{98.100}\)
bai1:tinh tong S=1.3+3.5+5.7+...+99.101
bai2 :tinh tong S=1.4+4.7+7.10+...+2017.2020
bai 3: tinh tong N=2.4+4.6+6.8+..+100.102
bai 4: tinh tóng=2.6+6.10+10.14+14.18+...+42.46+50.54
bai 5:tinh tongB=2^2+4^2+6^2+...+100^2
bai 6:C=1^2+3^2+...+100^2
bai7: biet 1^2+2^2+3^2+...+10^2=385 tinh tong 2^2+4^2+6^2+...+20^2
bai 8: tinh tong s=1^2+2^2+3^2+...+99^2
tính A=5/2.4+5/4.6+5/6.8+...+5/98.100
B=-2/1.2+-2/2.3+-2/3.4+...+-2/2015.2016
2/2.4+2/4.6+2/6.8+...+2/98.100
\(2.4+4.6+6.8+....+98.100\)
2.4+4.6+6.8+...+98.100/1.2+2.3+3.4+...+49.50. Tính
Tính nhanh:(1/2.4)+(1/4.6)+(1/6.8)+.....+(1/98.100)=
tính 2.4+3.5+4.6+5.7+6.8+7.9+8.10+...+97.99+98.100