Tính \(D=\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{2115}\)
Những câu hỏi liên quan
Tính nhanh :
\(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+\frac{3}{63}+....+\frac{3}{143}\)
Đặt \(A=\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+\frac{3}{63}+...+\frac{3}{143}\)
\(A=\frac{3}{1\cdot3}+\frac{3}{3\cdot5}+\frac{3}{5\cdot7}+...+\frac{3}{11\cdot13}\)
\(A=\frac{3}{2}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...-\frac{1}{13}\right)\)
\(A=\frac{3}{2}\left(1-\frac{1}{13}\right)\)
\(A=\frac{3}{2}\cdot\frac{12}{13}=\frac{18}{13}\)
Vậy ...........
Đúng 0
Bình luận (0)
\(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+\frac{3}{63}+...+\frac{3}{143}.\)
\(=\frac{3}{1\times3}+\frac{3}{3\times5}+\frac{3}{5\times7}+\frac{3}{7\times9}+...+\frac{3}{11\times13}\)
\(=\frac{2}{3}\times\left(\frac{2}{1\times3}+\frac{2}{3\times5}+\frac{2}{5\times7}+...+\frac{2}{11\times13}\right)\)
\(=\frac{2}{3}\times\left(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{2}{3}\times\left(1-\frac{1}{13}\right)\)
\(=\frac{2}{3}\times\frac{12}{13}\)
\(=\frac{8}{13}\)
Đúng 0
Bình luận (0)
\(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+\frac{3}{63}+...+\frac{3}{143}\)
\(=\frac{3}{1.3}+\frac{3}{3.5}+\frac{3}{5.7}+\frac{3}{7.9}+...+\frac{3}{11.13}\)
\(=\frac{3}{2}.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{3}{2}.\left(1-\frac{1}{13}\right)\)
\(=\frac{3}{2}\cdot\frac{12}{13}=\frac{18}{13}\)
Đúng 0
Bình luận (0)
Xem thêm câu trả lời
Tính nhanh :
\(C=\frac{1}{3}+\frac{-3}{4}+\frac{3}{5}+\frac{1}{57}+\frac{-1}{36}+\frac{1}{15}+\frac{-2}{9}\)
\(D=\frac{1}{2}+\frac{-1}{5}+\frac{-5}{7}+\frac{1}{6}+\frac{-3}{35}+\frac{1}{3}+\frac{1}{41}\)
\(E=\frac{-1}{2}+\frac{3}{5}+\frac{-1}{9}+\frac{1}{127}+\frac{-7}{18}+\frac{4}{35}+\frac{2}{7}\)
C = 1/3 + -3/4 + 3/5 + 1/57 + -1/36 + 1/15 + -2/9
C = ( 1/3 + 1/57 ) + ( -3/4 + -1/36 ) + ( 3/5 + 1/15 ) + -2/9
C = ( 19/57 + 1/57 ) + ( -27/36 + -1/36 ) + ( 9/15 + 1/15 ) + -2/9
C = 20/57 + -28/36 + 10/15 + -2/9
C = 20/57 + -7/9 + 2/3 + -2/9
C = ( 20/57 + 2/3 ) + ( -7/9 + -2/9 )
C = 58/57 + -1
C = 1/57
D = 1/2 + -1/5 + -5/7 + 1/6 + -3/35 + 1/3 + 1/41
D = ( 1/2 + 1/3 + 1/6 ) + ( -1/5 + -5/7 +-3/35 ) + 1/41
D = ( 3/6 + 2/6 + 1/6 ) + ( -7/35 + -25/35 + -3/35 ) + 1/41
D = 1 + -1 + 1/41
D = 1/41
E = -1/2 + 3/5 + -1/9 + 1/127 + -7/18 + 4/35 + 2/7
E = ( -1/2 + -1/9 + -7/18 ) + ( 3/5 + 4/35 ) + 1/127 + 2/7
E = ( -9/18 + -2/18 + -7/18 ) + ( 21/35 + 4/35 ) + 1/127 + 2/7
E = -1 + 5/7 + 1/257 + 2/7
E = -1 + ( 5/7 + 2/7 ) + 1/127
E = -1 + 1 + 1/127
E = 1/127
Đúng 0
Bình luận (0)
\(C=\frac{1}{3}+\frac{-3}{4}+\frac{3}{5}+\frac{1}{57}+\frac{-1}{36}+\frac{1}{15}+\frac{-2}{9}.\)
\(C=\left(\frac{1}{3}+\frac{3}{5}+\frac{1}{15}\right)-\left(\frac{3}{4}+\frac{1}{36}+\frac{2}{9}\right)+\frac{1}{57}\)
\(C=1-1+\frac{1}{57}\)
\(C=\frac{1}{57}\)
Đúng 0
Bình luận (0)
D=1/2+-1/5+-5/7+1/6+-3/35+1/3+1/41
D=(1/2+1/6+1/3)-(1/5+3/35+5/7)+1/41
D=1-1+1/41
D=1/41
E=-1/2+3/5+-1/9+1/127+-7/18+4/35+2/7
E=(3/5+4/35+2/7)-(1/2+1/9+7/18)+1/127
E=1-1+1/127
E=1/127
Đúng 0
Bình luận (0)
Xem thêm câu trả lời
tính
a, \(\frac{3}{7}+\frac{1}{2}-\frac{-3}{70}\)
b, \(\frac{3}{5}+\frac{-1}{25}-\frac{35}{100}\)
c, \(\frac{5}{12}-\frac{3}{-16}+\frac{3}{4}\)
d, \(\frac{5}{15}+\frac{4}{-12}+\frac{1}{7}-\frac{1}{-6}\)
Tính nhanh:
\(A=\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{4}+\frac{1}{7}-\frac{-3}{35}\right).\frac{-4}{3}}\)
giải chi tiết
Tính:Aleft(1-frac{2}{3}+frac{4}{3}right)-left(frac{4}{5}-1right)+left(frac{7}{5}+2right)Bleft(-3+frac{3}{4}-frac{1}{3}right):left(5+frac{2}{5}-frac{2}{3}right)Cleft(frac{3}{5}-frac{4}{15}right).left(frac{2}{7}-frac{3}{14}right)-left(frac{5}{9}-frac{7}{27}right).left(1-frac{3}{5}right)+left(1-frac{11}{12}right).left(1+frac{11}{12}right)Dfrac{left(frac{3}{10}-frac{4}{15}-frac{7}{20}right).frac{-5}{19}}{left(frac{1}{14}+frac{1}{7}-frac{-3}{35}right).frac{4}{3}}
Đọc tiếp
Tính:
A=\(\left(1-\frac{2}{3}+\frac{4}{3}\right)-\left(\frac{4}{5}-1\right)+\left(\frac{7}{5}+2\right)\)
B=\(\left(-3+\frac{3}{4}-\frac{1}{3}\right):\left(5+\frac{2}{5}-\frac{2}{3}\right)\)
C=\(\left(\frac{3}{5}-\frac{4}{15}\right).\left(\frac{2}{7}-\frac{3}{14}\right)-\left(\frac{5}{9}-\frac{7}{27}\right)\)\(.\left(1-\frac{3}{5}\right)+\left(1-\frac{11}{12}\right).\left(1+\frac{11}{12}\right)\)
D=\(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{-5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{35}\right).\frac{4}{3}}\)
Thực hiện phép tính (Tính nhanh nếu có thể) :
a) \(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{100}}\)
b) \(\frac{\frac{5}{12}+\frac{1}{8}-\frac{7}{11}}{\frac{49}{11}-\frac{7}{8}-\frac{35}{12}}\)
c)\(\frac{5-\frac{5}{3}-\frac{5}{9}-\frac{5}{27}}{-8+\frac{8}{3}+\frac{8}{9}+\frac{8}{27}}\div\frac{15-\frac{15}{11}-\frac{15}{121}}{16-\frac{16}{11}-\frac{16}{121}}\)
Cây a, bạn nhân cả 2 vế với 3
Lấy vế nhân với 3 trừ đi ban đầu tất cả chia 2
b) Tính như bình thường
Câu c hình như sai đề
Đúng 0
Bình luận (0)
Câu c đúng đề bạn ạ, mình nhầm, ngại viết lắm
Đúng 0
Bình luận (0)
Xem thêm câu trả lời
BÀi 1: Thực hiện phép tính ( tính nhanh nếu có thể)a.left(-frac{1}{2}right)-left(-frac{3}{5}right)+left(-frac{1}{9}right)+frac{1}{71}-left(-frac{2}{7}right)+frac{4}{35}-frac{7}{18}b.left(3-frac{1}{4}+frac{2}{3}right)-left(5-frac{1}{3}-frac{6}{5}right)-left(6-frac{7}{4}+frac{3}{2}right)c.frac{3}{5}:left(frac{-1}{15}-frac{1}{6}right)+frac{3}{5}:left(frac{1}{3}-1frac{1}{15}right)
Đọc tiếp
BÀi 1: Thực hiện phép tính ( tính nhanh nếu có thể)
a.\(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{71}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
b.\(\left(3-\frac{1}{4}+\frac{2}{3}\right)-\left(5-\frac{1}{3}-\frac{6}{5}\right)-\left(6-\frac{7}{4}+\frac{3}{2}\right)\)
c.\(\frac{3}{5}:\left(\frac{-1}{15}-\frac{1}{6}\right)+\frac{3}{5}:\left(\frac{1}{3}-1\frac{1}{15}\right)\)
1+\(\frac{3}{5}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{143}\)
1+\(\frac{3}{1.5}\)+\(\frac{3}{3.5}\)+\(\frac{3}{7.5}\)+...+\(\frac{3}{11.13}\)
1+( \(\frac{1}{1}\)-\(\frac{1}{5}\)+\(\frac{1}{3}\)-\(\frac{1}{5}\)+\(\frac{1}{7}\)-\(\frac{1}{5}\)+...+ \(\frac{1}{11}\)-\(\frac{1}{13}\))
1+ \(\frac{1}{13}\)
\(\frac{14}{13}\)
Mình chỉ làm theo ý hiểu nhưng cũng chẳng biết có đúng không ai thấy sai sửa hộ ạ.
Đúng 0
Bình luận (0)
thực hiên các phép tính tính :
a) \(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{35}\right).\frac{-4}{3}}\)
b) \(\frac{\left(1+2+3+...+100\right).\left(\frac{1}{3}-\frac{1}{5}-\frac{1}{7}-\frac{1}{9}\right).\left(6,3.12-21.3,6\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)