giải giúp mik, mik cần gấp Question giải giúp mik, mik cần gấp in progress 0 Môn Toán Vodka 5 years 2021-05-18T06:18:26+00:00 2021-05-18T06:18:26+00:00 2 Answers 25 views 0
Answers ( )
vote5*+ctlhn nhé
A = $\dfrac{1^{2}}{1.2}$ . $\dfrac{2^{2}}{2.3}$ . $\dfrac{3^{2}}{3.4}$ . $\dfrac{4^{2}}{4.5}$ . … .$\dfrac{99^{2} }{99.100}$
A = $\dfrac{1.1}{1.2}$ . $\dfrac{2.2}{2.3}$ . $\dfrac{3.3}{3.4}$ . $\dfrac{4.4}{4.5}$ . … . $\dfrac{99.99}{99.100}$
A= $\dfrac{1.1.2.2.3.3.4.4. … . 99.99}{1.2.2.3.4.4.5. … . 99.100}$
A = $\dfrac{(1.2.3.4. … . 99) . (1.2.3.4. … . 99)}{(1.2.3.4. … . 99) . ( 2.3.4.5. … . 100)}$
A = $\dfrac{1.2.3.4. … . 99}{2.3.4.5. … . 100}$
A = $\dfrac{1}{100}$
Vậy A = $\dfrac{1}{100}$