\(A=11x\left(\frac{5}{11x16}+\frac{5}{16x21}+\frac{5}{21x26}+\frac{5}{26x31}+\frac{5}{31x36}+\frac{5}{36x41}\right)\)

\(A=11x\left(\frac{16-11}{11x16}+\frac{21-16}{16x21}+\frac{26-21}{21x26}+...+\frac{41-36}{36x41}\right)\)

\(A=11x\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}+...+\frac{1}{36}-\frac{1}{41}\right)\)

\(A=11x\left(\frac{1}{11}-\frac{1}{41}\right)=11x\frac{30}{11x41}=\frac{30}{41}\)

A=\(\frac{55}{11.16}+\frac{55}{16.21}+...+\frac{55}{36.41}\)

A=\(11\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{36}-\frac{1}{41}\right)\)

A=\(11\left(\frac{1}{11}-\frac{1}{41}\right)\)

A=\(11.\frac{30}{451}\)

A=\(\frac{30}{41}\)

\(A=\frac{55}{11.16}+\frac{55}{16.21}+\frac{55}{21.26}+\frac{55}{26.31}+\frac{55}{31.36}+\frac{55}{36.41}\)

\(A=11\left(\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.26}+\frac{5}{26.31}+\frac{5}{31.36}+\frac{5}{36.41}\right)\)

\(A=11\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}+\frac{1}{26}-\frac{1}{31}+\frac{1}{31}-\frac{1}{36}+\frac{1}{36}-\frac{1}{41}\right)\)\(A=11\left(\frac{1}{11}-\frac{1}{41}\right)\)

\(A=11.\frac{30}{451}=\frac{30}{41}\)

A=55/11.16+55/16.21+55/21.26+55/26.31+55/31.36+55/36.41

  =11.(5/11.16+5/16.21+...+5/36.41)

  =11.(1/11-1/16+1/16-1/21+...+1/36-1/41)

  =11.(1/11-1/41)

  =11.30/451

  =30/41

sao biết đúng

lớp 5 mà

Bài 1:

Chiều cao của tam giác là:

12,56 x 2 : 8 = 3,14 (cm)

Đáp số: 3,14 cm

Bài 2:

a) 2 + 5/7 = 2/1 + 5/7 = 14/7 + 5/7 = 19/7

b) 13/5 - 2 = 13/5 - 2/1 = 13/5 - 10/5 = 3/5

c) 1/8 + 3/4 - 1/6 = 3/24 + 18/24 - 6/24 = 17/24

e) 12/5 - 2/2 + 7/7 - 6/6 = 12/5 - 1 + 1 - 1 = 12/5 - 1 = 12/5 - 5/5 = 7/5

Bài 3:

A = 55/11.16 + 55/16.21 + 55/21.26 + 55/26.31 + 55/31.36 + 55/36.41

A = 11.(1/11 - 1/16 + 1/16 - 1/21 + 1/21 - 1/26 + 1/26 - 1/31 + 1/31 - 1/36 + 1/36 - 1/41)

A = 11.(1/11 - 1/41)

A = 11.30/451

A = 30/41

Bài 1 :

Chiều cao tam giác đó là :

\(12,56.2:8=3,14\) ( cm )

Vậy : chiều cao tam giác đó là \(3,14\) cm.

Bài 2 :

a) \(2+\frac{5}{7}=\frac{14}{7}+\frac{5}{7}=\frac{19}{7}\)

b) \(\frac{13}{15}-2=\frac{13}{15}-\frac{30}{15}=-\frac{17}{15}\)

c) \(3-\frac{3}{8}=\frac{24}{8}-\frac{3}{8}=\frac{21}{8}\)

d) \(\frac{1}{8}+\frac{3}{4}-\frac{1}{6}=\left(\frac{1}{8}+\frac{6}{8}\right)-\frac{8}{48}=\frac{7}{8}-\frac{8}{48}=\frac{42}{48}-\frac{8}{48}=\frac{34}{48}=\frac{17}{24}\)

e) \(\frac{12}{5}-\frac{2}{2}+\frac{7}{7}-\frac{6}{6}=\frac{12}{5}-1+1-1=\frac{12}{5}-1=\frac{12}{5}-\frac{5}{5}=\frac{7}{5}\)

Bài 3 :

\(A=\frac{55}{11.16}+\frac{55}{16.21}+\frac{55}{21.26}+....+\frac{55}{36.41}\)

\(\Leftrightarrow A=11.\left(\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.26}+\frac{5}{26.31}+\frac{5}{31.36}+\frac{5}{36.41}\right)\)

\(\Leftrightarrow A=11.\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}+\frac{1}{26}-\frac{1}{31}+\frac{1}{31}-\frac{1}{36}+136\right)-\frac{1}{41}\)

\(\Leftrightarrow A=11.\left(\frac{1}{11}-\frac{1}{41}\right)=11.\frac{30}{451}=\frac{30}{41}\)

Vậy : \(A=\frac{30}{41}\)

Bài 1:

Chiều cao của tam giác là:

12,56 x 2 : 8 = 3,14 (cm)

Đáp số: 3,14 cm

Bài 2:

a) 2 + 5/7 = 2/1 + 5/7 = 14/7 + 5/7 = 19/7

b) 13/5 - 2 = 13/5 - 2/1 = 13/5 - 10/5 = 3/5

c) 1/8 + 3/4 - 1/6 = 3/24 + 18/24 - 6/24 = 17/24

e) 12/5 - 2/2 + 7/7 - 6/6 = 12/5 - 1 + 1 - 1 = 12/5 - 1 = 12/5 - 5/5 = 7/5

Bài 3:

A = 55/11.16 + 55/16.21 + 55/21.26 + 55/26.31 + 55/31.36 + 55/36.41

A = 11.(1/11 - 1/16 + 1/16 - 1/21 + 1/21 - 1/26 + 1/26 - 1/31 + 1/31 - 1/36 + 1/36 - 1/41)

A = 11.(1/11 - 1/41)

A = 11.30/451

A = 30/41

tick và theo dõi giúp mình nha

\(A=\frac{55}{11.16}+\frac{55}{16.21}+\frac{55}{21.26}+......+\frac{55}{36.41}\)

\(=11\left(\frac{5}{11.16}+\frac{5}{16.21}+......+\frac{5}{36.41}\right)\)

\(=11.\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+.......+\frac{1}{36}-\frac{1}{41}\right)\)

\(=11.\left(\frac{1}{11}-\frac{1}{41}\right)\)

\(=11.\frac{30}{451}=\frac{30}{41}\)

toán 5 | Diễn đàn HOCMAI - Cộng đồng học tập lớn nhất Việt Nam

\(A=\frac{55}{11X16}+\frac{55}{16X21}+\frac{55}{21X26}+\frac{55}{26X31}+\frac{55}{31X36}+\frac{55}{36X41}\)

\(A=11X\left(\frac{5}{11X16}+\frac{5}{16X21}+\frac{5}{21X26}+\frac{5}{26X31}+\frac{5}{31X36}+\frac{5}{36X41}\right)\)

\(A=11X\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}+\frac{1}{26}-\frac{1}{31}+\frac{1}{31}-\frac{1}{36}+\frac{1}{36}-\frac{1}{41}\right)\)

\(A=11X\left(\frac{1}{11}-\frac{1}{41}\right)\)

\(A=11X\frac{1}{11}-11X\frac{1}{41}\)

\(A=1-\frac{11}{41}\)

\(A=\frac{30}{41}\)

\(\frac{55}{16.21}\)chứ nhỉ.

A=\(\frac{55}{11.16}+\frac{55}{16.21}+\frac{55}{21.26}+\frac{55}{26.31}+\frac{55}{31.36}+\frac{55}{36.41}\)

A= 11.\(\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+\frac{1}{21}-\frac{1}{26}+....+\frac{1}{36}-\frac{1}{41}\right)\)

A= 11\(\left(\frac{1}{11}-\frac{1}{41}\right)\)

A= 11.\(\frac{30}{451}\)

A= \(\frac{30}{41}\)

\(\frac{30}{41}\)

\(A=\frac{55}{11.16}+\frac{55}{16.21}+\frac{55}{21.26}+....+\frac{55}{36.41}\)

    \(=11.\left(\frac{5}{11.16}+\frac{5}{16.21}+\frac{5}{21.26}+.....+\frac{5}{36.41}\right)\)

     \(=11.\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+....+\frac{1}{36}-\frac{1}{41}\right)\)

      \(=11.\left(\frac{1}{11}-\frac{1}{41}\right)\)

       \(=1-\frac{11}{41}\)

       \(=\frac{30}{41}\)

\(A=11\left(\frac{5}{11.6}+\frac{5}{16.21}+......+\frac{5}{36.41}\right)\)

\(=11\left(\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+.....+\frac{1}{36}-\frac{1}{41}\right)\)

\(=11\left(\frac{1}{11}-\frac{1}{41}\right)\)

\(=11.\frac{30}{451}=\frac{30}{41}\)

A=\(\frac{5^2}{1.6}\)+\(\frac{5^2}{6.11}\)+....+\(\frac{5^2}{26.31}\)=\(\frac{25}{1.6}\)+\(\frac{25}{6.11}\)+.....+\(\frac{25}{26.31}\)

\(\frac{1}{5}\)A=\(\frac{5}{1.6}\)+\(\frac{5}{6.11}\)+....+\(\frac{5}{26.31}\)=1-\(\frac{1}{6}\)+\(\frac{1}{6}\)-\(\frac{1}{11}\)+....+\(\frac{1}{26}\)-\(\frac{1}{31}\)=1-\(\frac{1}{31}\)=\(\frac{30}{31}\)

A=\(\frac{30}{31}\):\(\frac{1}{5}\)

A=\(\frac{150}{31}\)

150/31.

Tích cho mk nha.