- 6
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(本题满分8分)
- 19
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( )
- A.收敛且和为0
- B.收敛且和为a
- C.收敛且和为a-a<sub>1</sub>
- D.发散
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[ ]
- 22
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[ ]
- 25
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( )。
- A.<img src="//img1.yqda.net/question-name/7e/56f61068ea4496bf689153419f1e77.jpg" alt="" border="0" />
- B.<img src="//img1.yqda.net/question-name/88/d2e9ef4274719189479d1d124a237c.jpg" alt="" border="0" />
- C.<img src="//img1.yqda.net/question-name/9e/d99a488cffcdc5016ceca7b03dbcd5.jpg" alt="" border="0" />
- D.<img src="//img1.yqda.net/question-name/6f/18a07b98b722badaff0682ba60d90c.jpg" alt="" border="0" />
- 27
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( )
- 28
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下列等式成立的是( )