tính 1/(1-x)+1/(x+1)+2/(x^2+1)+4/(x^4+1) +8/(x^8+1)+16/(x^16+1) Mọi người giúp e với, e cần gấp 30/08/2021 Bởi Melanie tính 1/(1-x)+1/(x+1)+2/(x^2+1)+4/(x^4+1) +8/(x^8+1)+16/(x^16+1) Mọi người giúp e với, e cần gấp
$\dfrac{1}{1-x}+\dfrac{1}{x+1}+\dfrac{2}{x^2+1}+…..+\dfrac{16}{x^{16}+1}$ $ = \dfrac{1}{x+1}-\dfrac{1}{x-1} + \dfrac{2}{x^2+1} + ….+\dfrac{16}{x^{16}+1}$ $ = \dfrac{-2}{x^2-1} + \dfrac{2}{x^2+1} + \dfrac{4}{x^4+1} +….+\dfrac{16}{x^{16}+1}$ $ = \dfrac{-4}{x^4-1} + \dfrac{4}{x^4+1} + \dfrac{8}{x^8+1} + \dfrac{16}{x^{16}+1}$ $ = \dfrac{-8}{x^8-1} + \dfrac{8}{x^8+1} + \dfrac{16}{x^{16}+1}$ $ = \dfrac{-16}{x^{16}-1} + \dfrac{16}{x^{16}+1}$ $ = \dfrac{-32}{x^{32}-1}$ Bình luận
$\dfrac{1}{1-x}+\dfrac{1}{x+1}+\dfrac{2}{x^2+1}+…..+\dfrac{16}{x^{16}+1}$
$ = \dfrac{1}{x+1}-\dfrac{1}{x-1} + \dfrac{2}{x^2+1} + ….+\dfrac{16}{x^{16}+1}$
$ = \dfrac{-2}{x^2-1} + \dfrac{2}{x^2+1} + \dfrac{4}{x^4+1} +….+\dfrac{16}{x^{16}+1}$
$ = \dfrac{-4}{x^4-1} + \dfrac{4}{x^4+1} + \dfrac{8}{x^8+1} + \dfrac{16}{x^{16}+1}$
$ = \dfrac{-8}{x^8-1} + \dfrac{8}{x^8+1} + \dfrac{16}{x^{16}+1}$
$ = \dfrac{-16}{x^{16}-1} + \dfrac{16}{x^{16}+1}$
$ = \dfrac{-32}{x^{32}-1}$