Toán Lớp 6: E = 1/{1 . 2 . 3} + 1/{2 . 3 .4} + … + 1/{98 . 99 . 100}
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Toán Lớp 6: E = 1/{1 . 2 . 3} + 1/{2 . 3 .4} + … + 1/{98 . 99 . 100}
Comments ( 1 )
E = $\dfrac{1}{1.2.3}$ + $\dfrac{1}{2.3.4}$ + …. + $\dfrac{1}{98.99.100}$
E = $\dfrac{1}{2}$ x ( $\dfrac{2}{1.2.3}$ + $\dfrac{2}{2.3.4}$ + …. + $\dfrac{2}{98.99.100}$ )
E = $\dfrac{1}{2}$ x ( $\dfrac{1}{1.2}$ – $\dfrac{1}{2.3}$ + … + $\dfrac{1}{98.99}$ –
$\dfrac{1}{99.100}$ )
E = $\dfrac{1}{2}$ x ( $\dfrac{1}{1.2}$ – $\dfrac{1}{99.100}$ )
E = $\dfrac{1}{2}$ x ( $\dfrac{1}{2}$ – $\dfrac{1}{9900}$ )
E = $\dfrac{1}{2}$ x $\dfrac{4949}{9900}$
E = $\dfrac{4949}{19800}$