对于级数习下列结论中正确的是（).A.a＞1时,级数收敛B.a＜1时,级数发散C.a=1时,级数收敛D.a=1时,

A . 抽汽级数越多越好； B . 抽汽级数并不是越多越好； C . 采用回热循环的机组能够提高机组运行的经济性； D . 锅炉给水给水温度越高越好。

A . 必条件收敛 B . 必绝对收敛 C . 必发散 D . 可能收敛，也可能发散

A . 正确 B . 错误

A . 正确 B . 错误

A .https://assets.asklib.com/psource/1468559581866088141.png B .https://assets.asklib.com/psource/1468559586819096284.png C .https://assets.asklib.com/psource/1468559592527028732.png D .https://assets.asklib.com/psource/1468559597543088447.png

A . 必绝对收敛 B . 必条件收敛 C . 必发散 D . 可能收敛，也可能发散

A .https://assets.asklib.com/psource/1458180211399085116.png B .https://assets.asklib.com/psource/1458180219045036011.png C .https://assets.asklib.com/psource/1458180226382071632.png D .https://assets.asklib.com/psource/1458180232124094180.png

A . 2，3，4，… B . 2，5，8，… C . 3，6 D . 3，6，9，…

A .https://assets.asklib.com/psource/2015103008470426697.jpg B .https://assets.asklib.com/psource/201510300847227368.jpg C .https://assets.asklib.com/psource/2015103008473644669.jpg D .https://assets.asklib.com/psource/2015103008475312901.jpg

A .https://assets.asklib.com/psource/2015102616224486454.jpg （an+bn）发散B .https://assets.asklib.com/psource/2015102616224486454.jpg nbn发散C .https://assets.asklib.com/psource/2015102616224486454.jpg （an+bn）收敛、发散不确定D .https://assets.asklib.com/psource/2015102616224486454.jpg （an-bn）收敛

A．<img src='https://img2.soutiyun.com/shangxueba/ask/1926001-1929000/1928340/ct_jgzjgysm_jgzjgyschoose_00853(20093)1.jpg' /> B．<img src='https://img2.soutiyun.com/shangxueba/ask/1926001-1929000/1928340/ct_jgzjgysm_jgzjgyschoose_00853(20093)2.jpg' /> C．<img src='https://img2.soutiyun.com/shangxueba/ask/1926001-1929000/1928340/ct_jgzjgysm_jgzjgyschoose_00853(20093)3.jpg' /> D．<img src='https://img2.soutiyun.com/shangxueba/ask/1926001-1929000/1928340/ct_jgzjgysm_jgzjgyschoose_00853(20093)4.jpg' />

若级数习<img src='https://img2.soutiyun.com/ask/2020-11-26/975244241398906.png' />绝对收敛,则级数习<img src='https://img2.soutiyun.com/ask/2020-11-26/975244252374534.png' />必定();若级数习<img src='https://img2.soutiyun.com/ask/2020-11-26/97524427328373.png' />条件收敛,则级数<img src='https://img2.soutiyun.com/ask/2020-11-26/97524428376933.png' />必定().

A．像素位数越多，灰度级数越多 B．像素位数越多，图像细节越多 C．灰度级数越多，图像越细腻 D．灰度级数越少，图像质量越高 E．灰度级数越多，图像细节越多

A．在收敛圆内,幂级数绝对收敛 B．在收敛圆外,幂级数发散 C．在收敛圆周上,可能收敛,也可能发散 D．在收敛圆周上,条件收敛

设级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473223462229.jpg' />的绝对值级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473238100066.jpg' />发散，且其发散的结论是由比式判别法或根式判别法得到的，即我们有<img src='https://img2.soutiyun.com/ask/2021-01-14/979473272654042.jpg' />证明级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473324430004.jpg' />一定发散。

设<img src='https://img2.soutiyun.com/ask/2020-12-22/977477196762504.png' />必发散。若这两个级数都发散，上述结论是否成立？

若级数<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />a_n发散，<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />b_n发散，则有下列中何项结论（）？ A．<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />（a_n+b_n）发散 B．<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />_nb_n发散 C．<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />（a_n+b_n）收敛、发散不确定 D．<img src='https://img2.soutiyun.com/shangxueba/ask/17670001-17673000/17671850/2015102616224486454.jpg' />（a_n-b_n）收敛

设有两个级数(Ⅰ)<img src='https://img2.soutiyun.com/ask/2020-12-21/977391930577066.png' />和<img src='https://img2.soutiyun.com/ask/2020-12-21/977391941728704.png' /><img src='https://img2.soutiyun.com/ask/2020-12-21/977391950207188.png' />则下列结论中正确的是(). A.若u_n≤υ_n,且(II)收敛,则(I)一定收敛 B.若u_n≤υ_n,且(I)发散,则(II)一定发散 C.若0≤u_n≤v_n,且(Ⅱ)收敛,则(Ⅰ)一定收敛 D.若0≤u_n≤v_n,且(Ⅱ)发散,则(Ⅰ)一定发散

A．1级 B．0级 C．2级 D．1.5级

考虑级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979472776590669.jpg' />，由于1+1/n＞1，据p一级数的敛散性断言该级数收敛，是否正确？

此题为判断题(对，错)。