không kết thúc câu hỏi trước hy vọng gì câu hỏi sau
không kết thúc câu hỏi trước hy vọng gì câu hỏi sau
1,\(\frac{\frac{3}{3}-\frac{3}{5}+\frac{3}{11}+\frac{3}{13}}{\frac{7}{3}-\frac{7}{5}+\frac{5}{11}+\frac{5}{13}}\)
2,a,tim x biet:
a,\(\left(3x-2\right)^{10}=\left(3x-2\right)^6\) b\(\left(2x^2-13\right)^4=\left(-5\right)^4\)
3,tim so nguyen n de phan so sau co gia tri la 1 so nguyen va tinh gia tri do
a,A=\(\frac{3n+9}{n-4}\) b,B=\(\frac{6n+5}{2n-1}\)
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Tim ti so cua A va B ,biet rang
A=\(\frac{1}{1+1981}\)\(+\frac{1}{2+1982}+...+\frac{1}{n\left(1980+n\right)}+...+\frac{1}{25.2005}\)
B=\(\frac{1}{1.26}\)+\(\frac{1}{2.27}+...+\frac{1}{m\left(25+m\right)}+...+\frac{1}{1980+2005}\)
trong do Aco 25 so hang va B co 1980 so hang
cmr
B=\(\left(1-\frac{3}{2.4}\right)\left(1-\frac{3}{3.5}\right)\left(1-\frac{3}{4.6}\right)...\left(1-\frac{3}{n\left(n+2\right)}\right)< 2 \)Voi moi so nguyen duong n
Tim n để
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{n\left(n+1\right)}=\frac{2003}{2004}\)
Tim x biet neu \(\frac{x-2}{\left(a+3\right)\left(a-5\right)}=\frac{1}{2\left(a+3\right)}+\frac{1}{2\left(a+5\right)}\)
va x khac -3;5
\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{n+1}\right)\left(n\in N\right)\)
\(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+\frac{1}{4}\left(1+2+3+4\right)+.......+\frac{1}{20}\left(1+2+3+4....+20\right)\)
\(A=\left(\frac{1}{1^2}-1\right)\left(\frac{1}{2^2}-1\right)\left(\frac{1}{3^2}-1\right)...\left(\frac{1}{2015^2}-1\right)\left(\frac{1}{2016^2}-1\right);B=-\frac{1}{2}\). hãy so sanh a va b
So Sánh\(\left(-\frac{1}{2}\right)^{513}va\left(-\frac{1}{3}\right)^{315}\)
Cho A = \(\left(\frac{1}{2^2}-1\right)\left(\frac{1}{3^2}-1\right)....\left(\frac{1}{2013^2}-1\right)\left(\frac{1}{2014^2}-1\right)\) va B = \(\frac{-1}{2}\), So sanh A va B