sum from n=0 to infinity of (-0.5)^n

解答

n = 0 \sum \infty (- 0.5)^{n}

0.66666 \dots

求解步骤

n = 0 \sum \infty (- 0.5)^{n}

使用几何级数审敛法:

0.66666 \dots

= 0.66666 \dots

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