Tinh (tinh nhanh neu co the)
\(2-\frac{2}{3+\frac{1}{2}}\) va \(\frac{1-\frac{1}{\frac{3}{4}+1}}{3}\)
\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{264}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
tinh nhanh neu co the
\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{264}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{\frac{3}{4}\left(1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}\right)}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}\)\(+\frac{5}{8}\)
\(\frac{1}{2}\cdot\frac{3}{4}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}=1\)
Bai 1 : Thuc hien cac phep tinh ( tinh nhanh neu co the ) :
a) \(2\frac{1}{3}-\frac{1}{3}\)\(:\)\(\left[15\%+\left(-\frac{2}{3}+0,4.5\right)\right]\)
GIUP MK VOI NHA
MK DAG CAN GAP
AI LAM NHANH VA DUNG THI MK SE TICK CHO NHA ^ _ <
tinh hop li neu co the \(\frac{3}{4}.\frac{2}{5}-\frac{3}{10}.\frac{4}{3}\)
= \(\frac{6}{10}-\frac{12}{30}\)
= \(\frac{18}{30}-\frac{12}{30}\)
= \(\frac{6}{30}=\frac{1}{5}\)
\(\frac{3}{4}.\frac{2}{5}-\frac{3}{10}.\frac{4}{3}\)
\(=\frac{3.2}{4.5}-\frac{3.4}{10.3}\)
\(=\frac{3}{10}-\frac{4}{10}=\frac{-1}{10}\)
ha Le ha sai bét, zậy mà Tran Hoang Vy - cậu vẫn chọn đk àk, thử tính lại = mt cái koai, = -1/10 CHỨ KO PHẢI = 1/10
tinh nhanh
A=\(\frac{3}{1}+\frac{3}{1+2}+\frac{3}{1+2+3}+\frac{3}{1+2+3+4}+....+\frac{3}{1+2+3+.....+100}\)
\(A=\frac{3}{1}+\frac{3}{\frac{\left(2+1\right).2}{2}}+\frac{3}{\frac{\left(3+1\right).3}{2}}+....+\frac{3}{\frac{\left(100+1\right).100}{2}}\)
\(\Rightarrow A=\frac{3}{1}+\frac{6}{2.3}+\frac{6}{3.4}+...+\frac{6}{100.101}\)
\(\Rightarrow A=\frac{3}{1}+6.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-...-\frac{1}{101}\right)\)
\(\Rightarrow A=\frac{3}{1}+6.\left(\frac{1}{2}-\frac{1}{101}\right)\)
\(\Rightarrow A=\frac{3}{1}+\frac{6.99}{202}=\frac{297}{101}+\frac{3}{1}=\frac{600}{101}\)
kết quả k bik có sai k
\(\frac{x+5}{3}\)= \(\frac{5}{9}\)
\(\frac{x-2}{27}\)= \(\frac{3}{x-2}\)
tinh nhanh neu co the
\(\frac{3^4.2-3^6}{3^4.17+4.3^4}\)
\(\frac{x+5}{3}=\frac{5}{9}\)
=> ( x + 5 ) x 9 = 3 x 5
=> x + 5 = \(\frac{3\cdot5}{9}\)
=> x + 5 = \(\frac{5}{3}\)
=> x = \(\frac{-10}{3}\)
x+5/3=5/9
(x+5)x3/9=5/9
(x+5)x3=5
x+5=5:3
x+5=5/3
x=5/3-5
x=-10/3
x+5/3=5/9
[x+5]x9=5x3
x+5=[5x3]/9
x+5=5/3
x=5/3-5=-10/3
x-2/27=3/x-2
[x-2]^2=27x3
[x-2]^2=9^2
=>x-2=9
x=9+2=11
tinh nhanh
P=\(\frac{\frac{3}{7}-\frac{3}{13}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
\(P=\frac{\frac{3}{7}-\frac{3}{13}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
\(=\frac{3\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{37}\right)}{5\left(\frac{1}{7}-\frac{1}{17}+\frac{1}{37}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{-7\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)
\(=\frac{3}{5}+\frac{1}{-7}\)
\(=\frac{16}{35}\)
cho A=\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+.......+\frac{1}{2016}+\frac{1}{2017}\)
va B=\(\frac{2016}{1}+\frac{2015}{2}+\frac{2014}{3}+......+\frac{2}{2015}+\frac{1}{2016}\)
Tinh ti so \(\frac{A}{B}\)
tinh nhanh
\(\frac{1}{2^2}+\frac{2}{2^3}+\frac{3}{2^4}+...+\frac{9}{2^{10}}\)
\(\frac{1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{9}+\frac{1}{10}}{\frac{1}{1\times10}+\frac{1}{2\times9}+\frac{1}{3\times8}+....+\frac{1}{9\times2}+\frac{1}{10\times1}}\)
Tinh nhanh minh tich cho