Toán C=1/12+1/30+1/56 +…+1/2652. Cm C<1/4 help meeeee 16/07/2021 By Adalynn C=1/12+1/30+1/56 +…+1/2652. Cm C<1/4 help meeeee
Đáp án: C<1/4 Giải thích các bước giải: C =1/12+1/30+1/56+…+1/2652 C=1/3.4+1/5.6+1/7.8+…+1/51.52 <(1/2).(1/2.4+1/4.6+1/6.8+…+1/50.52)=1/2-1/4+1/4-1/6+…….+1/50-1/52 =1/2.(1/2-1/52)<1/2.1/2=1/4 =>C<1/4 (đpcm) Trả lời
Đáp án: Giải thích các bước giải: C = $\frac{1}{12}$ + $\frac{1}{30}$ + $\frac{1}{56}$ +…+ $\frac{1}{2652}$ = $\frac{1}{3×4}$ + $\frac{1}{5×6}$ + $\frac{1}{7×8}$ +…+ $\frac{1}{51×52}$ < $\frac{1}{2×4}$ + $\frac{1}{4×6}$ + $\frac{1}{6×8}$ +…+ $\frac{1}{50×52}$ =$\frac{1}{2}$($\frac{1}{2}$ – $\frac{1}{4}$ + $\frac{1}{4}$ – $\frac{1}{6}$ +…+ $\frac{1}{50}$ – $\frac{1}{52}$) = $\frac{1}{2}$( $\frac{1}{2}$ – $\frac{1}{52}$) < $\frac{1}{2}$ × $\frac{1}{2}$ = $\frac{1}{4}$ ⇒ C < $\frac{1}{4}$ (đpcm) Trả lời
Đáp án: C<1/4
Giải thích các bước giải:
C =1/12+1/30+1/56+…+1/2652
C=1/3.4+1/5.6+1/7.8+…+1/51.52
<(1/2).(1/2.4+1/4.6+1/6.8+…+1/50.52)=1/2-1/4+1/4-1/6+…….+1/50-1/52
=1/2.(1/2-1/52)<1/2.1/2=1/4
=>C<1/4 (đpcm)
Đáp án:
Giải thích các bước giải:
C = $\frac{1}{12}$ + $\frac{1}{30}$ + $\frac{1}{56}$ +…+ $\frac{1}{2652}$
= $\frac{1}{3×4}$ + $\frac{1}{5×6}$ + $\frac{1}{7×8}$ +…+ $\frac{1}{51×52}$
< $\frac{1}{2×4}$ + $\frac{1}{4×6}$ + $\frac{1}{6×8}$ +…+ $\frac{1}{50×52}$
=$\frac{1}{2}$($\frac{1}{2}$ – $\frac{1}{4}$ + $\frac{1}{4}$ – $\frac{1}{6}$ +…+ $\frac{1}{50}$ – $\frac{1}{52}$)
= $\frac{1}{2}$( $\frac{1}{2}$ – $\frac{1}{52}$) < $\frac{1}{2}$ × $\frac{1}{2}$ = $\frac{1}{4}$
⇒ C < $\frac{1}{4}$ (đpcm)