Tính \(A=1+2+5+17+...+\frac{3^{n-1}+1}{2}\)(nEZ+)
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cho mk hỏi :
Câu 1: Thực hiên phép tính bằng cách hợp lí.
1/ -43.92-46.27+46.41
2/-72.(15+49)+15.(-56+72)
3/(2^4).17.(-3)^0.(-5)^6.(-1^2n) (nEZ)
tính :
A = \(\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}\)+\(\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
\(A=\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
\(=\frac{3\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}{5\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}+\frac{1.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}{-7\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)
\(=\frac{3}{5}+\frac{-1}{7}\)
\(=\frac{21}{35}-\frac{5}{35}\)
\(=\frac{16}{35}\)
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\(A=\frac{3.\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}{5.\left(\frac{1}{7}-\frac{1}{17}-\frac{1}{37}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{7.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)
\(A=\frac{3}{5}+\frac{1}{7}=\frac{21}{35}+\frac{5}{35}=\frac{26}{35}\)
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1.thực hiện phép tính:
a, 24-{12-[(-10)-(-2)]}
b,2/3+1/3.(-2/3+5/6):2/3
2.tính nhanh:
a,\(-\frac{2}{5}+\left(-\frac{5}{9}+\frac{2}{5}\right)\)
b, 17/13-(4/13 - 11)
c,3/5.18/17+3/5.9/17-3/5.10/17
GIÚP IK GIÚP TUI VỚI! PLEASE
1/
a, 24 - {12 -[(-10)-(-2)]}
=24-{12-(-8)}
=24-20
=4
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b,\(\frac{2}{3}\)+\(\frac{1}{3}\).(\(\frac{-2}{3}\)+\(\frac{5}{6}\)):\(\frac{2}{3}\)
=\(\frac{2}{3}\)+\(\frac{1}{3}\).(\(\frac{-4}{6}\)+\(\frac{5}{6}\)):\(\frac{2}{3}\)
=\(\frac{2}{3}\)+\(\frac{1}{3}\).\(\frac{1}{6}\).\(\frac{3}{2}\)
=\(\frac{2}{3}\)+\(\frac{1}{18}\).\(\frac{3}{2}\)
=\(\frac{2}{3}\)+\(\frac{1}{6}\).\(\frac{1}{2}\)
=\(\frac{2}{3}\)+\(\frac{1}{12}\)
=\(\frac{8}{12}\)+\(\frac{1}{12}\)
=\(\frac{9}{12}\)=\(\frac{3}{4}\)
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2/
a,\(\frac{-2}{5}\)+(\(\frac{-5}{9}\)+\(\frac{2}{5}\))
=\(\frac{-2}{5}\)+\(\frac{-5}{9}\)+\(\frac{2}{5}\)
=(\(\frac{-2}{5}\)+\(\frac{2}{5}\))+\(\frac{-5}{9}\)
= 0+\(\frac{-5}{9}\)
= \(\frac{-5}{9}\)
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cho mk hỏi :
Câu 1: Thực hiên phép tính bằng cách hợp lí.
1/ -43.92-46.27+46.41
2/-72.(15+49)+15.(-56+72)
3/(2^4).17.(-3)^0.(-5)^6.(-1^2n) (nEZ)
Ai trả lời đúng minh tíck cho@@
1/ Ta có :\(-43.92-46.27+46.41\)
\(=\left(-86\right).46-46.27+46.41\)
\(=46.\left(-86-27+41\right)\)
\(=46.\left(-72\right)\)
\(=-3312\)
Tính:a) Afrac{(1+17)(1+frac{17}{2})(1+frac{17}{3})...(1+frac{17}{19})}{(1+19)(1+frac{19}{2})(1+frac{19}{3})...(1+frac{19}{17})}b) Bfrac{1}{-2}.frac{1}{3}+frac{1}{-3}.frac{1}{4}+...+frac{1}{-5}.frac{1}{10}c) C(1-frac{1}{1.2})+(1-frac{1}{2.3})+...+(1-frac{1}{2015.2016})d) Dfrac{frac{9}{1}+frac{8}{2}+frac{7}{3}+...+frac{1}{9}}{frac{1}{2}+frac{1}{3}+frac{1}{3}+...+frac{1}{10}}
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Tính:
a) \(A=\frac{(1+17)(1+\frac{17}{2})(1+\frac{17}{3})...(1+\frac{17}{19})}{(1+19)(1+\frac{19}{2})(1+\frac{19}{3})...(1+\frac{19}{17})}\)
b) \(B=\frac{1}{-2}.\frac{1}{3}+\frac{1}{-3}.\frac{1}{4}+...+\frac{1}{-5}.\frac{1}{10}\)
c) \(C=(1-\frac{1}{1.2})+(1-\frac{1}{2.3})+...+(1-\frac{1}{2015.2016})\)
d) \(D=\frac{\frac{9}{1}+\frac{8}{2}+\frac{7}{3}+...+\frac{1}{9}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{3}+...+\frac{1}{10}}\)
Bài 1:Tìm các số nguyên x để:a. 18/17+ 5/17 x/176/17+9/17b.1/3+3/35 x/210 4/7+ 3/5+ 1/3Bài 2: Tìm x biết ( 11/12+ 11/12.23+11/23.24+...+11/89.100)+ x5/3Bài 3: Tìm số nguyên n để biểu thức sau có giá trị là số nguyên: 4/n-1+ 6/n-1-3/n-1Bài 4:Tính tổng:a. 1/1.2+ 1/2.3+ 1/3.4+...+1/98.99+ 1/99.100 ; b. 3/2.5+ 3/5.8+ ...+ 3/17.20Bài 5: Tìm số nguyên x biếta. x: 3frac{1}{15} 1frac{1}{2}; b.x. 15/28 3/20; 5frac{4}{7}: x 13
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Bài 1:Tìm các số nguyên x để:
a. 18/17+ 5/17< x/17<6/17+9/17
b.1/3+3/35< x/210< 4/7+ 3/5+ 1/3
Bài 2: Tìm x biết ( 11/12+ 11/12.23+11/23.24+...+11/89.100)+ x=5/3
Bài 3: Tìm số nguyên n để biểu thức sau có giá trị là số nguyên: 4/n-1+ 6/n-1-3/n-1
Bài 4:Tính tổng:
a. 1/1.2+ 1/2.3+ 1/3.4+...+1/98.99+ 1/99.100 ; b. 3/2.5+ 3/5.8+ ...+ 3/17.20
Bài 5: Tìm số nguyên x biết
a. x: 3\(\frac{1}{15}\)= 1\(\frac{1}{2}\); b.x. 15/28= 3/20; 5\(\frac{4}{7}\): x =13
tính nhanh:
A=\(\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
giải chi tiết nhé các bạn
A=\(\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)
\(=\frac{3\left(\frac{1}{7}-\frac{1}{17}+\frac{1}{37}\right)}{5\left(\frac{1}{7}-\frac{1}{17}+\frac{1}{37}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{-7\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}\right)}\)
\(=\frac{3}{5}+\frac{1}{-7}=\frac{3}{5}-\frac{1}{7}\)
\(=\frac{21}{35}-\frac{5}{35}=\frac{16}{35}\)
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tính bằng cách hợp lí:a) frac{1+frac{1}{2}+frac{1}{3}+frac{1}{4}}{1-frac{1}{2}+frac{1}{3}-frac{1}{4}}:frac{13+frac{13}{2}+frac{13}{3}+frac{13}{4}}{17-frac{17}{2}+frac{17}{3}-frac{17}{4}}b)frac{0,125-frac{1}{5}+frac{1}{7}}{0,375-frac{3}{5}+frac{3}{7}}+frac{frac{1}{2}+frac{1}{3}-0,2}{frac{3}{4}+0,5-frac{3}{10}}giải hộ mk vs nhé (giải chí tiết hộ mk nhá)
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tính bằng cách hợp lí:
a) \(\frac{1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}}{1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}}:\frac{13+\frac{13}{2}+\frac{13}{3}+\frac{13}{4}}{17-\frac{17}{2}+\frac{17}{3}-\frac{17}{4}}\)
b)\(\frac{0,125-\frac{1}{5}+\frac{1}{7}}{0,375-\frac{3}{5}+\frac{3}{7}}+\frac{\frac{1}{2}+\frac{1}{3}-0,2}{\frac{3}{4}+0,5-\frac{3}{10}}\)
giải hộ mk vs nhé (giải chí tiết hộ mk nhá)
1. Tính :
a.\(\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}+\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}+\frac{3}{293}}+\frac{\frac{7}{12}+\frac{5}{6}-1}{5-\frac{3}{4}+\frac{1}{3}}\)
b.\(\left(1-\frac{1}{7}\right)\times\left(1-\frac{2}{7}\right)\times\left(1-\frac{3}{7}\right)\times......\times\left(1-\frac{10}{7}\right)\)
a) \(\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}+\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}+\frac{3}{293}}+\frac{\frac{7}{12}+\frac{5}{6}-1}{5-\frac{3}{4}+\frac{1}{3}}\) \(=\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}+\frac{\frac{5}{12}}{\frac{55}{12}}\)
\(=\frac{2}{3}+\frac{1}{11}=\frac{25}{33}\)
b) \(\left(1-\frac{1}{7}\right).\left(1-\frac{2}{7}\right)....\left(1-\frac{10}{7}\right)=\left(1-\frac{1}{7}\right).\left(1-\frac{2}{7}\right)...\left(1-\frac{7}{7}\right).\left(1-\frac{8}{7}\right).\left(1-\frac{9}{7}\right).\) \(\left(1-\frac{10}{7}\right)\) = 0
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a)\(\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}+\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}+\frac{3}{293}}+\frac{\frac{7}{12}+\frac{5}{6}-1}{5-\frac{3}{4}+\frac{1}{3}}\)
\(=\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}+\frac{\frac{7}{12}+\frac{10}{12}-\frac{12}{12}}{\frac{60}{12}-\frac{9}{12}+\frac{4}{12}}\)
\(=\frac{2}{3}+\frac{\frac{5}{12}}{\frac{55}{12}}\)
\(=\frac{2}{3}+\frac{1}{11}\)
\(=\frac{25}{33}\)
b)\(\left(1-\frac{1}{7}\right)\cdot\left(1-\frac{2}{7}\right)\cdot...\cdot\left(1-\frac{10}{7}\right)\)
Ta nhận thấy trong tích này có 1 thừa số là\(\left(1-\frac{7}{7}\right)=0\)nên tích trên sẽ bằng 0.
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Ta có \(\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}+\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}+\frac{3}{293}}+\frac{\frac{7}{12}+\frac{5}{6}-1}{5-\frac{3}{4}+\frac{1}{3}}\)
= \(\frac{\frac{2}{7}+\frac{2}{5}+\frac{2}{17}+\frac{2}{293}}{\frac{3}{7}+\frac{3}{5}+\frac{3}{17}+\frac{3}{293}}+\frac{\frac{7}{12}+\frac{10}{12}-\frac{12}{12}}{\frac{60}{12}-\frac{9}{12}+\frac{4}{12}}\)
= \(\frac{2\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}{3\left(\frac{1}{7}+\frac{1}{5}+\frac{1}{17}+\frac{1}{293}\right)}+\frac{\frac{5}{12}}{\frac{55}{12}}\)
= \(\frac{2}{3}+\frac{1}{11}\)
= \(\frac{25}{33}\)
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