Question

\(C=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\) 

Ai nhanh và đúng nhất mk sẽ tik!!!

Answer 1

\(C=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)

\(C=1\times\frac{1}{2}+\frac{1}{2}\times\frac{1}{3}+\frac{1}{3}\times\frac{1}{4}+\frac{1}{4}\times\frac{1}{5}+\frac{1}{5}\times\frac{1}{6}\)

\(C=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)

\(C=1-\frac{1}{6}\)

\(C=\frac{5}{6}\)

Answer 2

\(=\frac{5}{6}nhé\)

Answer 3

\(C=\frac{30}{60}+\frac{10}{60}+\frac{5}{60}+\frac{3}{60}+\)\(\frac{2}{60}\)

\(C=\frac{30+10+5+3+2}{60}\)

\(C=\frac{50}{60}=\frac{5}{6}\)

Answer 4

\(\frac{1}{2}\)\(+\)\(\frac{1}{6}\)\(+\)\(\frac{1}{12}\)\(+\)\(\frac{1}{20}\)\(+\)\(\frac{1}{30}\)

=    \(\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}\right)\)\(+\)\(\frac{1}{20}\)\(+\)\(\frac{1}{30}\)

=           \(\frac{3}{4}\)\(+\)\(\frac{1}{12}\)

=                 \(\frac{5}{6}\)

♥ Nếu thấy đúng thì ủng hộ mk nha ♥

Answer 5

C= \(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{30}\)

\(C=\frac{1}{2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{5.6}\)

\(C=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}\)

\(C=\frac{1}{1}-\frac{1}{4}+\frac{1}{5}-\frac{1}{6}\)

\(C=\frac{60}{60}-\frac{15}{60}+\frac{12}{60}-\frac{10}{60}\)

\(C=\frac{60-15+12-10}{60}\)

\(C=\frac{47}{60}\)

vay \(C=\frac{47}{60}\)

Answer 6

\(C=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)

\(C=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\)

\(C=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)

\(C=1-\frac{1}{6}\)

\(C=\frac{5}{6}\)

GIẢI THÍCH: -\(-\frac{1}{2}+\frac{1}{2}=0\)

          \(-\frac{1}{3}+\frac{1}{3}=0\)

                    ....

            \(-\frac{1}{5}+\frac{1}{5}=0\)

Vậy chỉ còn \(1-\frac{1}{6}\)