Tính
E = \(\frac{2^2}{1.3}+\frac{3^2}{2.4}+\frac{4^2}{3.5}+.............+\frac{50^2}{49.51}\)
D = \(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}......\frac{2499}{2500}\) DẤU "." Ở DÂN LÀ DẤU NHÂN
C = \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{999}\right).\left(1-\frac{1}{1000}\right)\)
G = \(\left(1-\frac{1}{11}\right).\left(1-\frac{2}{11}\right)......\left(1-\frac{20}{11}\right)\)
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