Ta có: 1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2.3+1/3.4+1/4.5+…+1/99.100 =>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2-1/3+1/3-1/4+1/4-1/5+…+1/99-1/100 =>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2-1/100<1/2 =>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2 Chúc hok tốt!! Trả lời
Ta có : 1/3^2 < 1/2.3 1/4^2 < 1/3.4 … 1/100^2 < 1/99.100 => 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2.3 + 1/3.4 + … + 1/99.100 => 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 – 1/3 + 1/3 – 1/4 + … + 1/99 – 1/100 => 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 – 1/100 => 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 (đpcm) Học tốt~~ Trả lời
Ta có:
1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2.3+1/3.4+1/4.5+…+1/99.100
=>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2-1/3+1/3-1/4+1/4-1/5+…+1/99-1/100
=>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2-1/100<1/2
=>1/3^2+1/4^2+1/5^2+1/6^2+…+1/100^2<1/2
Chúc hok tốt!!
Ta có :
1/3^2 < 1/2.3
1/4^2 < 1/3.4
…
1/100^2 < 1/99.100
=> 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2.3 + 1/3.4 + … + 1/99.100
=> 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 – 1/3 + 1/3 – 1/4 + … + 1/99 – 1/100
=> 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 – 1/100
=> 1/3^2 + 1/4^2 + … + 1/100^2 < 1/2 (đpcm)
Học tốt~~