Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
3/4-3/2+1/2:5/12-1/4
3/4-3/2+1/2.12/5-1/2
3/4-3/2+6/5-1/2
3/4-6/4+6/5-1/2
-3/4+6/5-1/2
-15/20+24/20-10/20
9/20-10/20
-1/20
\(0,5.1\frac{1}{3}.75\%:\frac{2}{5}+\frac{3}{5}\)
\(=\frac{1}{2}.\frac{4}{3}.\frac{3}{4}:\frac{2}{5}+\frac{3}{5}\)
\(=\frac{1}{2}.\frac{4}{3}.\frac{3}{4}.\frac{5}{2}+\frac{3}{5}\)
\(=\frac{5}{4}+\frac{3}{5}\)
\(=\frac{37}{20}\)
\(0,5.1\frac{1}{3}.75\%:\frac{2}{5}+\frac{3}{5}\)
\(=\frac{1}{2}.\frac{4}{3}.\frac{3}{4}:\frac{2}{5}+\frac{3}{5}\)
\(=\frac{1}{2}.\frac{4}{3}.\frac{3}{4}.\frac{5}{2}+\frac{3}{5}\)
\(=\frac{1.4.3.5}{2.3.4.2}+\frac{3}{5}\)
\(=\frac{5}{4}+\frac{3}{5}\)
\(=\frac{37}{20}\)
~Học tốt~
a)=-7/21+8/24
=-1/3+1/3
=0
b)=-3/5.(2/7+5/7)+23/5
=-3/5.7/7+23/5
=-3/5.1+23/5
=-3/5+23/5
=20/5=4
c)=75/100-11/2+5/10:5/12+1/4
=3/4-11/2+1/2:5/12+1/4
=3/4+-11/2+1/2.12/5+1/4
=3/4+-22/4+6/5+1/4
=-19/4+6/5+1/4
=(-19/4+1/4)+6/5
=-18/4+6/5
=-9/2+6/5
=-45/10+12/10
=-23/10
Ta có
\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+....+\frac{1}{11^2}>\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{11.12}\)
Mà
\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{11.12}=\frac{3-2}{2.3}+\frac{4-3}{3.4}\frac{5-4}{4.5}+...+\frac{12-11}{11.12}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{11}-\frac{1}{12}=\frac{1}{2}-\frac{1}{12}=\frac{5}{12}\)
Nên \(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{11^2}>\frac{5}{12}\)
1/2^2+1/3^2+1/4^2+....+1/11^2<1/(2.3)+1/(3.4)+1/(4.5)+.....+1/(11.12)
=1/2-13+1/3-1/4+1/5+.....+1/11-1/12
=1/2-1/12=5/12
VẬY A<5/12
ks cho mình nhé
\(75\%-1\frac{1}{2}+0,5:\frac{5}{12}\)
\(=\frac{3}{4}-\frac{3}{2}+\frac{1}{2}.\frac{12}{5}\)
\(=\frac{3}{4}-\frac{3}{2}+\frac{6}{5}\)
\(=\frac{15}{20}-\frac{30}{20}+\frac{24}{20}\)
\(=\frac{9}{20}\)
\(75\%-1\frac12+0,5:\frac{5}{12}\)
\(=\frac34-\frac32+\frac12\cdot\frac{12}{5}\)
\(=\frac34-\frac32+\frac65=\frac{15}{20}-\frac{30}{20}+\frac{24}{20}\)
\(=\frac{9}{20}\)