49+2=
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(A=\left(\dfrac{1}{49}-\dfrac{1}{2^2}\right)\left(\dfrac{1}{49}-\dfrac{1}{3^2}\right)\cdot...\cdot\left(\dfrac{1}{49}-\dfrac{1}{100^2}\right)\)
\(=\left(\dfrac{1}{49}-\dfrac{1}{7^2}\right)\left(\dfrac{1}{49}-\dfrac{1}{2^2}\right)\cdot...\cdot\left(\dfrac{1}{49}-\dfrac{1}{100^2}\right)\)
\(=\left(\dfrac{1}{49}-\dfrac{1}{49}\right)\left(\dfrac{1}{49}-\dfrac{1}{4}\right)\cdot...\cdot\left(\dfrac{1}{49}-\dfrac{1}{10000}\right)\)
=0
\(\dfrac{11}{49}\times\dfrac{1}{2}+\dfrac{11}{49}:\dfrac{5}{4}-\dfrac{11}{49}\times\dfrac{3}{4}\)
\(=\dfrac{11}{49}\times\dfrac{1}{2}+\dfrac{11}{49}\times\dfrac{4}{5}-\dfrac{11}{49}\times\dfrac{3}{4}\)
\(=\dfrac{11}{49}\times\left(\dfrac{1}{2}+\dfrac{4}{5}-\dfrac{3}{4}\right)\)
\(=\dfrac{11}{49}\times\left(\dfrac{10}{20}+\dfrac{16}{20}-\dfrac{15}{20}\right)\)
\(=\dfrac{11}{49}\times\dfrac{11}{20}\)
\(=\dfrac{121}{980}\)
Chúc bạn học tốt
`@` `\text {Ans}`
`\downarrow`
\(\dfrac{11}{49}\times\dfrac{1}{2}+\dfrac{11}{49}\div\dfrac{5}{4}-\dfrac{11}{49}\times\dfrac{3}{4}\)
`=`\(\dfrac{11}{49}\times\dfrac{1}{2}+\dfrac{11}{49}\times\dfrac{4}{5}-\dfrac{11}{49}\times\dfrac{3}{4}\)
`=`\(\dfrac{11}{49}\times\left(\dfrac{1}{2}+\dfrac{4}{5}-\dfrac{3}{4}\right)\)
`=`\(\dfrac{11}{49}\times\dfrac{11}{20}\)
`=`\(\dfrac{121}{980}\)
= \(\left(\frac{1}{49}-\frac{1}{3^2}\right)...\left(\frac{1}{49}-\frac{1}{7^2}\right)..\left(\frac{1}{49}-\frac{1}{49^2}\right)=\left(\frac{1}{49}-\frac{1}{3^2}\right)..\left(\frac{1}{49}-\frac{1}{49}\right)...\left(\frac{1}{49}-\frac{1}{49^2}\right)\)
= \(\left(\frac{1}{49}-\frac{1}{3^2}\right)....0...\left(\frac{1}{49}-\frac{1}{49^2}\right)=0\)
P = 1/49+2/48+3/47+...+48/2+49/1
Cộng 1 váo mỗi p/s trong 48 p/s đầu , trừ p/s cuối đi 48 ta đượ
P=(1/49+1)+(2/48+1)+...+(48/2+1)+1
P= 50/49+50/48+....+50/2+50/50
Đưa ps cuối lên đầu
P=50/50+50/49+50/48+...+50/2
=50.(1/50+1/49+1/48+...+1/4+1/3+1/2)
=50.S
VậyS/P=1/50
49 + 2 = 51
tk mk mk nhanh nhất
49+2=51