1-1/3-1/9-1/27-1/81-1/243 - 知识问答

1-1/3-1/9-1/27-1/81-1/243-1/729-1/2187

1个回答

1-1/3-1/9-1/27-1/81-1/243-1/729-1/2187
=1-(1/3+1/9+1/27+1/81+1/243+1/729+1/2187)
=1-(1/3)*[1-(1/3)^7]/[1-(1/3)]
=1-(1/3)*[1-(1/2187)]/(2/3)
=1-(1/2)*(2186/2187)
=1094/2187

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