ai nhanh giup minh di roi minh cho nick "lien quan mobile" rank vang

B=1/16+ 6/16.26+ 6/26.36+ ..................+ 6/2006.2016

B=1/16+ 6. (1/16.26+ 1/26.36 +.................+ 1/2006.2016)

10B=1/16+6.(1/16- 1/2016)

10B=7.1/16 - 1/336

10B=7/16 - 1/336

10B=73/168

B=73/1680

làm hơi tắt bạn cố hiểu nhé

tớ là "nam tử hán đại trượng phu" nên tớ hứa là tớ làm .Kết bạn với tớ đi,tớ nhắn tin cho

 \(B=\frac{1}{16}+\frac{6}{16.26}+\frac{6}{26.36}+\frac{6}{36.46}+...+\frac{6}{2006.2016}\) =\(B=\frac{1}{16}+\frac{3}{5}\left(\frac{10}{16.26}+\frac{10}{26.36}+\frac{10}{36.46}+...+\frac{10}{2006.2016}\right)\)

\(B=\frac{1}{16}+\frac{3}{5}\left(\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}+\frac{1}{36}-\frac{1}{46}+...+\frac{1}{2006}-\frac{1}{2016}\right)\)

\(B=\frac{1}{16}+\frac{3}{5}\left(\frac{1}{16}-\frac{1}{2016}\right)\)

đến đây thì ổn rồi

\(=\dfrac{1}{16}+\dfrac{1}{16}-\dfrac{1}{26}+...+\dfrac{1}{2006}-\dfrac{1}{2016}\)

=1/8-1/2016

=251/2016

nhân với 1/6

nhân với 1/6 cả 2 vế rồi nhân cả 2 vế với 10

\(B=\frac{1}{16}+\frac{6}{16.26}+\frac{6}{26.36}+...+\frac{6}{2006.2016}\)

\(B=\frac{1}{16}+6\left(\frac{1}{16.26}+\frac{6}{26.36}+...+\frac{6}{2006.2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}\left(\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}+...+\frac{1}{2006}-\frac{1}{2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}\left(\frac{1}{16}-\frac{1}{2016}\right)\)

\(B=\frac{1}{16}+\frac{6}{10}.\frac{125}{2016}\)

\(B=\frac{1}{16}+\frac{25}{672}\)

\(B=\frac{67}{672}\)

x-y-z=0=>x=y+z

=>z=x-y;=>y=x-z

\(=>B=\left(1-\frac{z}{x}\right)\left(1-\frac{x}{y}\right)\left(1-\frac{y}{z}\right)=\left(1-\frac{x-y}{x}\right)\cdot\left(1-\frac{y+z}{y}\right)\cdot\left(1+\frac{x-z}{z}\right)\)

Câu a cậu ghi sai đầu bài rồi hay sao í! phải là \(\frac{6}{36.46}\) chứ

Ta có x-y-z=0 suy ra x=z+y;y=x-z;-z=y-x

B=(1-z/x)(1-x/y)(1+y/z)

B=((x-z)/x)((y-x)/y)((z+y)/z)

B=(y/x)(-z/y)(x/z)

B=(-z.y.x)/(z.y.x)

B=-1

nhanh lên ngày mai mk hk rùi

a, \(A=\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{299.300}\)

\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{299}-\dfrac{1}{300}\)

\(=1-\dfrac{1}{300}=\dfrac{299}{300}\)

Vậy \(A=\dfrac{299}{300}\)

b, \(B=\dfrac{10^2}{16.26}+\dfrac{10^2}{26.36}+...+\dfrac{10^2}{86.96}\)

\(=10\left(\dfrac{10}{16.26}+\dfrac{10}{26.36}+...+\dfrac{10}{86.96}\right)\)

\(=10\left(\dfrac{1}{16}-\dfrac{1}{26}+\dfrac{1}{26}-\dfrac{1}{36}+...+\dfrac{1}{86}-\dfrac{1}{96}\right)\)

\(=10\left(\dfrac{1}{16}-\dfrac{1}{96}\right)\)

\(=10.\dfrac{5}{96}=\dfrac{25}{48}\)

Vậy...

a,\(A=\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+.......+\dfrac{1}{299.300}\)

\(A=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{299}-\dfrac{1}{300}\)

(do \(\dfrac{n}{a.\left(a+n\right)}=\dfrac{1}{a}-\dfrac{1}{a+n}\) với mọi \(a\in N\)*)

\(A=\dfrac{1}{1}-\dfrac{1}{300}=\dfrac{299}{300}\)

a) \(A=\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3.4}+....+\dfrac{1}{299\cdot300}\)

\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{299}-\dfrac{1}{300}\)

\(=1-\dfrac{1}{300}=\dfrac{299}{300}\)

b) \(B=\dfrac{10^2}{16\cdot26}+\dfrac{10^2}{26\cdot36}+\dfrac{10^2}{36\cdot46}+...+\dfrac{10^2}{86.96}\)

\(\dfrac{B}{10}=\dfrac{10}{16\cdot26}+\dfrac{10}{26\cdot36}+\dfrac{10}{36\cdot46}+...+\dfrac{10}{86\cdot96}\)

\(\dfrac{B}{10}=\dfrac{1}{16}-\dfrac{1}{26}+\dfrac{1}{26}-\dfrac{1}{36}+\dfrac{1}{36}-\dfrac{1}{46}+...+\dfrac{1}{86}-\dfrac{1}{96}\)

\(\dfrac{B}{10}=\dfrac{1}{16}-\dfrac{1}{96}=\dfrac{5}{96}\)

\(\Rightarrow B=\dfrac{5}{96}\cdot10=\dfrac{25}{48}\)

\(\frac{15.\left(\frac{1}{616}.\frac{1}{6.16}.\frac{1}{6.16}\right)}{33.\left(\frac{1}{6.16}.\frac{1}{6.16}.\frac{1}{6.16}\right)}=\frac{15}{35}\)