$\frac{9}{2.4}$ + $\frac{25}{4.6}$ +$\frac{49}{6.8}$ + ...+ $\frac{10201}{100.102}$
= ( $\frac{9}{2.4}$ -1) +( $\frac{25}{4.6}$ -1) + ($\frac{49}{6.8}$ -1)+ ...+( $\frac{10201}{100.102}$ -1) + 1.50
= $\frac{1}{2.4}$ + $\frac{1}{4.6}$ +$\frac{1}{6.8}$ + ...+ $\frac{1}{100.102}$ + 50
= $\frac{1}{2}$ ( $\frac{2}{2.4}$ + $\frac{2}{4.6}$ +$\frac{2}{6.8}$ + ...+ $\frac{2}{100.102}$) + 50
= $\frac{1}{2}$ ( $\frac{1}{2}$ -$\frac{1}{4}$ + $\frac{1}{4}$ - $\frac{1}{6}$+$\frac{1}{6}$ - $\frac{1}{8}$+ ...+ $\frac{1}{100}$ -$\frac{1}{102}$ ) + 50
= $\frac{1}{2}$( $\frac{1}{2}$ - $\frac{1}{102}$) + 50
= $\frac{1}{2}$ . $\frac{25}{51}$ + 50
= $\frac{5125}{102}$
Có j thắc mắc thì hỏi mk nha ^o^
