D = \(\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{2115}\)
D = \(3.\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{45.47}\right)\)
D = \(3.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{45}-\frac{1}{47}\right)\)
D = \(3.\left(1-\frac{1}{47}\right)\)
D = \(3.\frac{46}{47}=\frac{138}{47}\)
D = 3/3 + 3/15 + 3/35 + ... + 3/2115
D = 3/2(2/1*3 + 2/3*5 + 2/5*7 + ... + 2/45*47)
D = 3/2(1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + ... + 1/45 - 1/47)
D = 3/2(1 - 1/47)
D = 3/2*46/47
D = 69/47
D\(=\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{2115}\)
\(=3.\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{45.47}\right)\)
\(=3.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{45}-\frac{1}{47}\right)\)
\(=3.\left(1-\frac{1}{47}\right)\)
\(=3.\frac{46}{47}\)
\(=\frac{138}{47}\)
#hok tốt#
\(D=\frac{3}{3}+\frac{3}{15}+\frac{3}{35}+...+\frac{3}{2115}\)
\(D=3.\left(\frac{1}{3}+\frac{1}{15}+\frac{1}{35}+...+\frac{1}{2115}\right)\)
\(D=3.\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{45.47}\right)\)
\(D=3.\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{45}-\frac{1}{47}\right)\)
\(D=3.\left[1+\left(\frac{1}{3}-\frac{1}{3}\right)+\left(\frac{1}{5}-\frac{1}{5}\right)+...+\left(\frac{1}{45}-\frac{1}{45}\right)-\frac{1}{47}\right]\)
\(D=3.\left[1-\frac{1}{47}\right]\)
\(D=3.\frac{46}{47}\)
\(D=\frac{138}{47}\)
~ Hok tốt ~
mẹ chúng m ngáo hết à
1/1*3 = 1 - 1/3 ????
1 - 1/3 = 2/3
tử phải = hiệu của mẫu ok
