請問無窮等比級數
設x為實數 已知無窮等比級數x+x(2x+3)+x(2x+3)^2+.............收斂
則x的範圍?
這一題不就是 公比 -1<r=2x+3 <-1 或 x=0 的時候會收斂
有書寫說 -2<x<-1 但x不等於 -(3/2) (因為公比不為0)...這條件要考慮嗎?
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