Tính \(\frac{A}{B}\)biết :
A = \(\frac{1}{21}\)+\(\frac{1}{2.22}\)+ ...............+ \(\frac{1}{n.\left(n+20\right)}\)+........................+\(\frac{1}{1993.2013}\)
B = \(\frac{1}{1994}\)+ \(\frac{1}{2.1995}\)+..................+\(\frac{1}{n.\left(n+1993\right)}\)+...................+\(\frac{1}{20.2013}\)
Tính A/B biết :A= 1/21+1/2.22+...+ 1/n.(n+20)...+ 1/1993.2013, B= 1/1994+1/2.1995+...+ 1/n.(n+1993)+...+ 1/20.2013
GIÚP MIK VS NHA
Cho \(A=\frac{1}{1.21}+\frac{1}{2.22}+\frac{1}{3.23}+......+\frac{1}{80.100}\)
\(B=\frac{1}{1.81}+\frac{1}{2.82}+\frac{1}{3.83}+....+\frac{1}{20.100}\). Tính \(\frac{A}{B}\)
bai 1 :thuc hien phep tinh
a)\(\frac{-5}{2}:\left(\frac{3}{4}-\frac{1}{2}\right)\) b) \(11\frac{3}{13}-\left(2\frac{4}{7}+5\frac{3}{13}\right)\) c)\(\left(\frac{-5}{24}+0,75+\frac{7}{12}\right):\left(-2\frac{1}{4}\right)^2\)
AI LAM NHANH VA DUNG THI MK SE TICK CHO NHA
MK DAG CAN GAP !!!!!!! CAC BAN LAM NHANH LEN NHA
tinh gia try bieu thuc
A=\(\left[\frac{1}{7}+\frac{1}{23}-\frac{1}{1009}\right]:\left[\frac{1}{23}+\frac{1}{7}-\frac{1}{1009}+\frac{1}{7}\times\frac{1}{23}\times\frac{1}{1009}\right]+1:\left[30\times1009-160\right]\)
ai lam dung co ca cach lam cho 1 like
So sanh S=\(\frac{1}{5}+\frac{1}{9}+\frac{1}{10}+\frac{1}{40}+\frac{1}{42}voi\frac{1}{2}\)
minh can cach lam
ai nhanh minh tick
C=\(\frac{3}{3.5}\)+\(\frac{3}{5.7}\)+\(\frac{3}{7.9}\)+...+\(\frac{3}{47.49}\)
NHANH LEN NHE MINH CAN GAP LAM AI DUNG MINH TICH CHO !
Tìm x, biết:
\(\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+...+\frac{2}{x\left(x+1\right)}\)
ai làm đúng, nhanh mk cho 10 tick
Tính \(\frac{A}{B}\)
A=\(\frac{1}{1.21}+\frac{1}{2.22}+\frac{1}{3.23}+.....+\frac{1}{80.100}\)
B=\(\frac{1}{1.81}+\frac{1}{2.82}+\frac{1}{3.83}+.....+\frac{1}{20.100}\)
