0,1621963429

= 0,1621963429 tk m nhé

=0.1621963429

k mik nha

lôi cái máy tính cầm tay ra là giải đc ấy mà

\(\frac{1}{7}+\frac{1}{91}+\frac{1}{247}+\frac{1}{475}+\frac{1}{755}+\frac{1}{1147}\)

\(=\frac{1}{7}+\frac{1}{7.13}+\frac{1}{13.19}+\frac{1}{19.25}+\frac{1}{25.31}+\frac{1}{31.37}\)

\(=\frac{1}{6}\left(1-\frac{1}{37}\right)\)

\(=\frac{1}{6}.\frac{36}{37}\)

\(=\frac{6}{37}\)

\(\frac{1}{7}+\frac{1}{91}+\frac{1}{247}+\frac{1}{475}+\frac{1}{755}+\frac{1}{1147}\)

\(=\frac{1}{1.7}+\frac{1}{7.13}+\frac{1}{13.19}+\frac{1}{19.25}+\frac{1}{25.31}+\frac{1}{31.37}\)

\(=\frac{1}{6}.\left(\frac{6}{1.7}+\frac{6}{7.13}+\frac{6}{13.19}+\frac{6}{19.25}+\frac{6}{25.31}+\frac{6}{35.37}\right)\)

\(=\frac{1}{6}.\left(1-\frac{1}{7}+\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{19}+\frac{1}{19}-\frac{1}{25}+\frac{1}{25}-\frac{1}{31}+\frac{1}{31}-\frac{1}{37}\right)\)

\(=\frac{1}{6}.\left(1-\frac{1}{37}\right)\)

\(=\frac{1}{6}.\frac{36}{37}=\frac{6}{37}\)

~ Hok tốt ~

\(\frac{1}{6}\left(\frac{6}{7}+\frac{6}{91}+\frac{6}{247}+\frac{6}{475}+\frac{6}{755}+\frac{6}{1147}\right)\)

\(=\frac{1}{6}\left(\frac{6}{1\cdot7}+\frac{6}{7\cdot13}+\frac{6}{13\cdot19}+\frac{6}{19\cdot25}+\frac{6}{25\cdot31}+\frac{6}{31\cdot37}\right)\)

\(=\frac{1}{6}\left(1-\frac{1}{7}+\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{19}+\frac{1}{19}-\frac{1}{25}+\frac{1}{25}-\frac{1}{31}+\frac{1}{31}-\frac{1}{37}\right)\)

\(=\frac{1}{6}\left(1-\frac{1}{37}\right)\)

\(\frac{1}{6}\left(\frac{37}{37}-\frac{1}{37}\right)=\frac{1}{6}\cdot\frac{36}{37}=\frac{1\cdot6\cdot6}{6\cdot37}=\frac{6}{37}\)

1/7 + 1 / 91 + 1/247 + 1/475 + 1/755 + 1/1147

= 1/1.7 + 1/7.13 + 1/13.19 + 1/19.25 + 1/25.31 + 1/31.37

= 1/6. 6/1.7 + 1/6 . 6/7.13 + 1/6 . 6/13.19 + 1/6 . 6/19.25 + 1/6. 25.31 + 1/6. 31.37

= 1/6 ( 6/1.7 + 6/7.13 + 6/13.19 + 6/19.25 + 6/25.31 + 6/31.37 )

= 1/6. ( 1/1 - 1/7 + 1/7 - 1/13 +1/13 - 1/19 + 1/19 - 1/25 + 1/25 - 1/31 + 1/31 - 1/37

= 1/6 . ( 1/1 - 1/37 )

= 1/6. ( 37/37 - 1/37)

= 1/6 . 36/37

= 6 / 37

Chúc bn học tốt!

1/7 + 1 / 91 + 1/247 + 1/475 + 1/755 + 1/1147

= 1/1.7 + 1/7.13 + 1/13.19 + 1/19.25 + 1/25.31 + 1/31.37

= 1/6. 6/1.7 + 1/6 . 6/7.13 + 1/6 . 6/13.19 + 1/6 . 6/19.25 + 1/6. 25.31 + 1/6. 31.37

= 1/6 ( 6/1.7 + 6/7.13 + 6/13.19 + 6/19.25 + 6/25.31 + 6/31.37 )

= 1/6. ( 1/1 - 1/7 + 1/7 - 1/13 +1/13 - 1/19 + 1/19 - 1/25 + 1/25 - 1/31 + 1/31 - 1/37

= 1/6 . ( 1/1 - 1/37 )

= 1/6. ( 37/37 - 1/37)

= 1/6 . 36/37

= 6 / 37

= 6/37 nha

đúng 10000000000000000000000000% đó nếu có sai thì trách cái máy tính của mk nha vì k pải mk tính mờ là nó tính....

tk mk nha đg âm 439 kìa....

T_T

lấy máy tính mà tính

bằng 5/31 nha bạn

a: \(\dfrac{1}{7}+\dfrac{1}{91}+\dfrac{1}{247}+\dfrac{1}{475}+\dfrac{1}{775}+\dfrac{1}{1147}\)

\(=\dfrac{1}{1\cdot7}+\dfrac{1}{7\cdot13}+\dfrac{1}{13\cdot19}+\dfrac{1}{19\cdot25}+\dfrac{1}{25\cdot31}+\dfrac{1}{31\cdot37}\)

\(=\dfrac{1}{6}\left(\dfrac{6}{1\cdot7}+\dfrac{6}{7\cdot13}+\dfrac{6}{13\cdot19}+\dfrac{6}{19\cdot25}+\dfrac{6}{25\cdot31}+\dfrac{6}{31\cdot37}\right)\)

\(=\dfrac{1}{6}\left(1-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{13}+...+\dfrac{1}{31}-\dfrac{1}{37}\right)\)

\(=\dfrac{1}{6}\left(1-\dfrac{1}{37}\right)=\dfrac{1}{6}\cdot\dfrac{36}{37}=\dfrac{6}{37}\)

b: Sửa đề:\(\dfrac{3}{5\cdot8}+\dfrac{11}{8\cdot19}+\dfrac{12}{19\cdot31}+\dfrac{80}{31\cdot101}+\dfrac{99}{101\cdot200}\)

\(=\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{19}+\dfrac{1}{19}-\dfrac{1}{31}+\dfrac{1}{31}-\dfrac{1}{101}+\dfrac{1}{101}-\dfrac{1}{200}\)

\(=\dfrac{1}{5}-\dfrac{1}{200}=\dfrac{39}{200}\)

\(\dfrac{1}{7}+\dfrac{1}{91}+\dfrac{1}{247}+\dfrac{1}{475}+\dfrac{1}{775}+\dfrac{1}{1147}\)

\(=\dfrac{1}{1.7}+\dfrac{1}{7.13}+\dfrac{1}{13.19}+\dfrac{1}{19.25}+\dfrac{1}{25.31}+\dfrac{1}{31.37}\)

\(=\dfrac{1}{6}\left(1-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{13}+\dfrac{1}{13}-\dfrac{1}{19}+\dfrac{1}{19}-\dfrac{1}{25}+\dfrac{1}{25}-\dfrac{1}{31}+\dfrac{1}{31}-\dfrac{1}{37}\right)\)

\(=\dfrac{1}{6}\left(1-\dfrac{1}{37}\right)\)

\(=\dfrac{1}{6}.\dfrac{36}{37}\)

\(=\dfrac{6}{37}\)

\(#Wendy.Dang\)

\(\frac{1}{7}+\frac{1}{91}+\frac{1}{247}+\frac{1}{475}+\frac{1}{775}+\frac{1}{1147}\)

\(=\frac{1}{1\cdot7}+\frac{1}{7\cdot13}+\frac{1}{13\cdot19}+...+\frac{1}{31\cdot37}\)

\(=\frac{1}{6}\left(\frac{6}{1\cdot7}+\frac{6}{7\cdot13}+\frac{6}{13\cdot19}+...+\frac{6}{31\cdot37}\right)\)

\(=\frac{1}{6}\left(1-\frac{1}{7}+\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{19}+...-\frac{1}{31}-\frac{1}{37}\right)\)

\(=\frac{1}{6}\left(1-\frac{1}{37}\right)\)

\(=\frac{1}{6}\cdot\frac{36}{37}=\frac{6}{37}\)

Tổng cần tính bằng:\(\frac{1}{1.7}\)+\(\frac{1}{7.13}\)+\(\frac{1}{13.19}\)+\(\frac{1}{19.25}\)+\(\frac{1}{25.31}\)+\(\frac{1}{31.37}\)=(\(\frac{1}{1}\)-\(\frac{1}{7}\)+\(\frac{1}{7}\)-\(\frac{1}{13}\)+...+\(\frac{1}{31}\)\(\frac{1}{37}\)):3 =(\(1\)-\(\frac{1}{37}\)):3=\(\frac{12}{37}\)

\(\frac{12}{37}\)kà kết quả nha bạn. chúc bạn học tốt. ( kik mình nha)