Specific approximation of sums with integrals

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These two approximations are given in my book. $$ \sum_{k=0}^m\left(\frac{k}{m}\right)^n\approx\int_0^m\left(\frac{x}{m}\right)^ndx\tag{1}$$

$$\sum_{i=m+1}^n\frac{1}{i-1}\approx\int_m^n\frac{1}{x}dx\tag{2}$$

I would like some explanation of why they are true and what does the "approximately" mean. Is it convergence in the limit or is it just close.

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HINT

Write the RHS integral as a Riemann sum with the constant rectangle width. Pretty sure you intended $\int_0^m (x/m)^n dx$