Tính tổng :
\(\frac{3}{2x4}+\frac{3}{4x6}+....+\frac{3}{96x98}+\frac{3}{98x100}\)
Tính:
\(\frac{1}{2x4}+\frac{1}{4x6}+\frac{1}{6x8}+..................+\frac{1}{96x98}+\frac{1}{98x100}\)
Nếu giải đúng có lời giải ,sẽ có 2 tick
\(\frac{1}{2x4}+\frac{1}{4x6}+...+\frac{1}{96x98}+\frac{1}{98x199}=\frac{2}{2x4}+\frac{2}{4x6}+...+\frac{2}{99x100}\)
\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...-\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{100}=\frac{49}{100}\)
A x2 = \(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+............+\frac{1}{98}-\frac{1}{100}\)
A x2 = \(\frac{49}{100}\)
A = \(\frac{49}{200}\)
Tính:
\(\frac{1}{2x4}+\frac{1}{4x6}+\frac{1}{6x8}+...........+\frac{1}{96x98}+\frac{1}{98x100}\)
giải nhanh ,có lời giải cơ sở sẽ có tick
1/2*(2/2*4+2/4*6+...+2/98*100)=1/2*(1/2-1/4+1/4-1/6+...+1/98-1/100)
=1/2*(1/2-1/100)
=1/2*49/100
=49/200
k nha bạn
\(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{96.98}+\frac{1}{98.100}\)
\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{96}-\frac{1}{98}+\frac{1}{98}-\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{100}\)
\(=\frac{49}{100}\)
cho mình tròn 1550 nhé bạn
=2/2 4+2/4 6+2/6 8+...+2/96 98+2/98 100
=2/2-2/4+2/4-2/6+2/6-2/8+...+2/96-2/98+2/98-2/100
=2/2-2/100
=99/100
\(\frac{1}{2x4}+\frac{1}{4x6}+\frac{1}{6x8}+.............+\frac{1}{96x98}+\frac{1}{98x100}\)
Ai trả lời thì ghi cả cách làm giúp mình với nha ! Thank you
\(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{98.100}\)
\(=\frac{1}{2}\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+....+\frac{2}{98.100}\right)\)
\(=\frac{1}{2}\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+....+\frac{1}{98}-\frac{1}{100}\right)\)
\(=\frac{1}{2}\left(\frac{1}{2}-\frac{1}{100}\right)=\frac{49}{200}\)
Đáp số: \(\frac{49}{200}\).
Đúng 100% luôn!
Ai tk cho mình mình tk lại.
\(\frac{1}{2x4}+\frac{1}{4x6}+\frac{1}{6x8}+......+\frac{1}{96x98}+\frac{1}{98x100}.\)
Chú giải: x là dấu nhân
Giải thích mình sẽ **** !!!!!
Đặt A=\(\frac{1}{2x4}+\frac{1}{4x6}+.........+\frac{1}{98x100}\)
2A=\(\frac{2}{2x4}+\frac{2}{4x6}+.............+\frac{2}{98x100}\)
2A=\(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+..........+\frac{1}{98}-\frac{1}{100}\)
2A=\(\frac{1}{2}-\frac{1}{100}\)
2A=\(\frac{49}{100}\)
A=\(\frac{49}{100}:2\)
A=\(\frac{49}{200}\)
câu này mk gặp rùi nhưng ko biết cách làm
\(\frac{1}{2x4}\)+ \(\frac{1}{4x6}\) + \(\frac{1}{6x8}\)+ ............+\(\frac{1}{96x98}\)+\(\frac{1}{98x100}\)
giai ro ra nhe, phan mau so la phep nhan do nha
A=\(\frac{1}{2x4}+\frac{1}{4x6}+\frac{1}{6x8}+......+\frac{1}{98x100}\)
\(A=\frac{1}{2\times4}+\frac{1}{4\times6}+\frac{1}{6\times8}+...+\frac{1}{98\times100}\)
\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{96}-\frac{1}{98}+\frac{1}{98}-\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{100}\)
\(=\frac{50}{100}-\frac{1}{100}\)
\(=\frac{49}{100}\)
Vậy: \(A=\frac{49}{100}\)
Ta có:\(2A=2\left(\frac{1}{2.4}+\frac{1}{4.6}+....+\frac{1}{98.100}\right)\)
\(=\frac{2}{2.4}+\frac{2}{4.6}+....+\frac{2}{98.100}\)
\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+....+\frac{1}{98}-\frac{1}{100}\)
\(=\frac{1}{2}-\frac{1}{100}=\frac{49}{100}\)
\(\Rightarrow A=\frac{49}{100}\div2=\frac{49}{200}\)
Vậy giá trị của A là \(\frac{49}{200}\)
Giải nhanh giúp nha !
1/2x4+1/4x6+1/4x8...1/96x98+1/98x100
Tính tổng
tính:1/2x4+1/4x6+1/6x8+.....+1/96x98+1/98x100=.......
1/2.4 + 1/4.6 + 1/6.8 + ... + 1/96.98 + 1/98.100
= 1/2.(2/2.4 + 2/4.6 + 2/6.8 + ... + 2/96.98 + 2/98.100)
= 1/2.(1/2 - 1/4 + 1/4 - 1/6 + ... + 1/96 - 1/98 + 1/98 - 1/100)
= 1/2.(1/2 - 1/100)
= 1/2.49/100
= 49/200
Tính
1/2x4+1/4x6+1/6x8+...+1/96x98+1/98x100=?