A=20/1.21+20/2.22+...+20/80.100
=1-1/21+1/2-1/22+...+1/80-1/100
=(1+1/2+...+1/80)-(1/21+1/22+...+1/100)
80B=80/1.81+80/2.82+...+8/20.100
=1-1/81+1/2-1/82+...+1/20-1/100
=(1+1/2+...+1/20)-(1/81+1/82+...+1/100)
=(1+1/2+1/3+...+1/20+1/21+1/22+...+1/80)-(1/21+1/22+...1/80+1/81+1/82+...1/100)
=>20A=80B
=>A=4B
Câu 24 : Cho A = 1.21 + 1/2.22 + 1/3.23 + ... + 1/80.100 ; B = 1/1.81 + 1/2.82 + 1/3.83 + ... + 1/20.100 . Tính A/B
Cho \(A=\dfrac{1}{1.21}+\dfrac{1}{2.22}+\dfrac{1}{3.23}+...+\dfrac{1}{80.100}\);
\(B=\dfrac{1}{1.81}+\dfrac{1}{2.82}+\dfrac{1}{3.83}+...+\dfrac{1}{20.100}\).
Tính \(\dfrac{A}{B}\).
tính a/b biết a=1/1.21 + 1/2.22 + 1/3.23 + ... +1/80.100; b=1/1.81 + 1/2.82 + 1/3.82 + ... + 1/20.100
Cho \(A=\frac{1}{1.21}+\frac{1}{2.22}+\frac{1}{3.23}+......+\frac{1}{80.100}\)
\(B=\frac{1}{1.81}+\frac{1}{2.82}+\frac{1}{3.83}+....+\frac{1}{20.100}\). Tính \(\frac{A}{B}\)
cho a = 1/1.21 + 1/2.22+...+1/80.100 b= 1/1.81 + 1/2.82+...+1/20.100 tính a/b
Tính \(\frac{A}{B}\)
A=\(\frac{1}{1.21}+\frac{1}{2.22}+\frac{1}{3.23}+.....+\frac{1}{80.100}\)
B=\(\frac{1}{1.81}+\frac{1}{2.82}+\frac{1}{3.83}+.....+\frac{1}{20.100}\)
A=\(\frac{1}{1.21}\)+\(\frac{1}{2.22}\)+\(\frac{1}{3.23}\)+...+\(\frac{1}{80.100}\)và B=\(\frac{1}{1.81}\)+\(\frac{1}{2.82}\)+\(\frac{1}{3.83}\)+...+\(\frac{1}{20.100}\).Tính \(\frac{A}{B}\)
A=1/1.21+ 1/2.22 +1/3.23+..........1/80.100 B=1/1.81+1/2.82+1/3.83+............+1/20.100
tính A/B
các bạn giải giúp mình nha. Thanks !
Câu 24 : Cho A = 1/1.21 + 1/2.22 + 1/3.23 + ...+ 1/80.10
