\(=\frac{1}{3}\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{94.97}\right).\)
\(=\frac{1}{3}\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{94}-\frac{1}{97}\right)\)
\(=\frac{1}{3}\left(\frac{1}{1}-\frac{1}{97}\right)\)
\(=\frac{1}{3}.\frac{96}{97}\)
\(=\frac{32}{97}\)
học tốt
3A = 3(1/1.4 + 1/4.7 + 1/7.10 + ...... + 1/94.97)
3A=1 - 1/4 + 1/4 - 1/7 + 1/7 - 1/10 + 1/10 - ........ - 1/97
3A = 1-1/97
3A = 96/97
A = 32/97
Oke nha bạn
A = \(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+....+\frac{1}{94.97}\)
\(3A=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{94.97}\)
\(3A=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{94}-\frac{1}{97}\)
\(3A=1-\frac{1}{97}\)
\(3A=\frac{96}{97}\)
\(A=\frac{32}{97}\)
3A=\(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{94.97}\)
3A=\(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{94}-\frac{1}{97}\)
A=\(\frac{1}{3}-\frac{1}{97.3}\)
A=1/1.4 + 1/4.7 + 1/7.10 +.......+1/94.97
A=1/3.( 3/1.4 + 3/4.7 + 3/7.10 +......+3/94.97 )
A=1/3.( 1/1.4 + 1/4.7 + 1/7.10 +.....+1/94.97 )
A=1/3.( 1/1 - 1/4 + 1/4 - 1/7 + 1/7 - 1/10 +.......+1/94 - 1/97 )
A=1/3.( 1/1 - 1/97 )
A=1/3.96/97
A=32/97
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