已知信号[img=234x25]18038ce58ed3edd.png[/img]，[img=54x29]18038ce597af125.png[/img]是信号[img=32x25]18038ce59f138aa.png[/img]的傅里叶变换。则[img=71x29]18038ce5a6df0e4.png[/img] （ ）。
A: 5
B: 4
C: 3
D: 1
A: 5
B: 4
C: 3
D: 1
举一反三
- 已知信号[img=234x25]1803bd65f12cb3a.png[/img]，[img=54x29]1803bd65fa167e8.png[/img]是信号[img=32x25]1803bd660241ad0.png[/img]的傅里叶变换。则[img=71x29]1803bd6609a1fe6.png[/img] （ ）。 A: 5 B: 4 C: 3 D: 1
- 已知信号[img=234x25]180330b989dd5a3.png[/img]，[img=54x29]180330b99305a43.png[/img]是信号[img=32x25]180330b99b2f6e4.png[/img]的傅里叶变换。则[img=71x29]180330b9a30c3f0.png[/img] （ ）。 A: 5 B: 4 C: 3 D: 1
- 求不定积分[img=121x54]17da653839aa6ae.png[/img]； （ ） A: log(x^2 + 3*x + 25/4)/4 + (5*atan(x/2 + 3/4))/4 B: log(x^2 + 3*x + 25/4)/4 C: (5*atan(x/2 + 3/4))/4 D: log(x^2 + 3*x + 25/4)/4 - (5*atan(x/2 + 3/4))/4
- 原电池（-）Pt︱Fe[img=17x22]1803dd54de61136.png[/img](1 mol·L[img=17x22]1803dd54e7299c0.png[/img]),Fe[img=17x22]1803dd54f0030fb.png[/img](1 mol·L[img=17x22]1803dd54fa39c0d.png[/img])‖Ce[img=17x22]1803dd5502f9d6b.png[/img]( mol·L[img=17x22]1803dd550b82a7d.png[/img]) ,Ce[img=17x22]1803dd55130efd2.png[/img]( mol·L[img=17x22]1803dd551af174c.png[/img]) ︱Pt(+)的电池反应是( )。 A: Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] = Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img] B: Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img] = Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] C: Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img] = Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] D: Ce[img=17x22]1803dd5534dbdef.png[/img] + Fe[img=17x22]1803dd552ca7541.png[/img] = Ce[img=17x22]1803dd552375aee.png[/img] + Fe[img=17x22]1803dd553dc33d1.png[/img]
- 求不定积分[img=115x46]17da65382f8e1b9.png[/img]； （ ） A: x - (5*log(x + 1))/4 - (3*log(x - 3)) B: (5*log(x + 1))/4 - (3*log(x - 3)) C: x - (5*log(x + 1))/4 - (3*log(x - 3))/4 D: (5*log(x + 1))/4 - (3*log(x - 3))/4