\(A=\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{40.41}+\frac{7}{10.57}\)tính tổng A
Tính tổng A=\(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{40.41}+\frac{7}{10.57}\)
tính tổng A = \(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{40.41}+\frac{7}{10.57}=?\)
tính tổng A=\(\frac{4}{7\cdot31}+\frac{6}{7.41}+\frac{9}{40.41}+\frac{7}{10.57}\)
Tính B=\(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}+\frac{13}{57.14}\)
Đây là toán lớp 6.
=>1/5B= 4/7.5.31 +6/7.5.41+9/5.10.41+7/5.10.57+13/57.5.14
=>1/5B=4/31.35+6/35.41+....+13/57.70
=>1/5B=1/31-1/35+1/35-1/41+...+1/57-1/70
=>1/5B=1/31-1/70
=>1/5B=39/2170
=>B=39/2170:1/5
=>B=39/424
Ta có:
\(\frac{B}{5}=\frac{4}{35.31}+\frac{6}{35.41}+\frac{9}{50.41}+\frac{7}{50.57}+\frac{13}{57.70}\)
\(=\frac{35-31}{35.31}+\frac{41-35}{35.41}+\frac{50-41}{50.41}+\frac{57-50}{50.57}+\frac{70-57}{57.70}\)
\(=\frac{1}{31}-\frac{1}{35}+\frac{1}{35}-\frac{1}{41}+\frac{1}{41}-\frac{1}{50}+\frac{1}{50}-\frac{1}{57}+\frac{1}{57}-\frac{1}{70}\)
\(=\frac{1}{31}-\frac{1}{70}\)
\(\rightarrow B=5\cdot\left(\frac{1}{31}-\frac{1}{70}\right)\)
\(=5\cdot\frac{39}{2170}\)
\(=\frac{39}{434}\)
Vậy B=\(\frac{39}{434}\)
Ta có:
\(\frac{B}{5}=\frac{4}{35.31}+\frac{6}{35.41}+\frac{9}{50.41}+\frac{7}{50.57}+\frac{13}{57.70}\)
\(=\frac{1}{31}-\frac{1}{35}+\frac{1}{35}-\frac{1}{41}+\frac{1}{41}-\frac{1}{50}+\frac{1}{50}-\frac{1}{57}+\frac{1}{57}-\frac{1}{70}\)
\(=\frac{1}{31}-\frac{1}{70}\)
\(\Rightarrow B=5\left(\frac{1}{31}-\frac{1}{70}\right)\)
\(=\frac{39}{434}\)
tính A = \(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}+\frac{1958}{57.403}\)
Đáp án là \(\frac{64}{403}\)bạn nhé !
A= 5 x (4/31.7.5 + 6/7.5.41 + 9/41.10.5 + 7/ 10.5.57 + 1958/57.403.5)
= 5 x (4/31.35 + 6/35.41 + 9/41.50 + 7/50.57 + 1958/57.2015)
=5 x (1/31 - 1/35 + 1/35 - 1/41 + 1/41 - 1/50 + 1/50 - 1/57 + 1/57 - 1/2015)
= 5 x (1/31 - 1/2015)
= 5 x (65/2015 - 1/2015)
= 5 x 64/2015
= 320/2015 = 64/403
\(A=\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}\)
Tính A
\(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}=?\)
Tính tỉ số A/B biết
A=\(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}\)
B=\(\frac{7}{19.31}+\frac{5}{19.43}+\frac{5}{23.43}+\frac{11}{23.57}\)
nhân A với 5
nhân B với 2
Tỉ số là 5/2 bạn tự giải đầy đủ nhé mình ko bít viết kí hiệu PS
Chúc bạn học tốt!!
tính tỉ số \(\frac{a}{b}\)\(b=\frac{7}{19.31}+\frac{5}{19.43}+\frac{3}{23.43}+\frac{11}{23.57}\)\(a=\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}\)