tính: A=$\frac{1}{150}$ + $\frac{1}{300}$ + $\frac{1}{500}$ + $\frac{1}{750}$ + $\frac{1}{1050}$

tính: A=$\frac{1}{150}$ + $\frac{1}{300}$ + $\frac{1}{500}$ + $\frac{1}{750}$ + $\frac{1}{1050}$

0 bình luận về “tính: A=$\frac{1}{150}$ + $\frac{1}{300}$ + $\frac{1}{500}$ + $\frac{1}{750}$ + $\frac{1}{1050}$”

  1. $A=\dfrac{1}{150} + \dfrac{1}{300} + \dfrac{1}{500} + \dfrac{1}{750} + \dfrac{1}{1050}$

    $⇔ A= \dfrac{1}{10.15} + \dfrac{1}{15.20} + \dfrac{1}{20.25} + \dfrac{1}{25.30} + \dfrac{1}{30.35}$

    $⇔ 5A= \dfrac{5}{10.15} + \dfrac{5}{15.20} + \dfrac{5}{20.25} + \dfrac{5}{25.30} + \dfrac{5}{30.35}$

    $⇔ 5A = \dfrac{1}{10} – \dfrac{1}{15} + \dfrac{1}{15} – \dfrac{1}{20} + \dfrac{1}{20} – \dfrac{1}{25} + \dfrac{1}{25} – \dfrac{1}{30} + \dfrac{1}{30} – \dfrac{1}{35}$

    $⇔ 5A = \dfrac{1}{10} – \dfrac{1}{35}$

    $⇔ 5A  = \dfrac{1}{14}$

    $⇔ A = \dfrac{\dfrac{1}{14}}{5}$

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