梵高生前只卖出过一幅画作，而现在他的作品却成了无价之宝。这说明了：https://p.ananas.chaoxing.com/star3/origin/d2584510cb92405074f6f70e08f56d8c.jpg
举一反三
- 已知信号f(t)如图所示，则其傅里叶变换为。https://p.ananas.chaoxing.com/star3/origin/ddb8ffc4b3d85599b2fe584dfc9896ed.png
- 以下说法正确的是 https://p.ananas.chaoxing.com/star3/origin/32620d45b840963fcfd2a9e499329436.png https://p.ananas.chaoxing.com/star3/origin/be2489a6491756903a1a67528363e754.png https://p.ananas.chaoxing.com/star3/origin/c5d98544629d58d5c134ed8bc9743922.png https://p.ananas.chaoxing.com/star3/origin/eef7c4f0c58f9f292270fbd5e9600bd3.png
- 设函数,而,其中,则为https://p.ananas.chaoxing.com/star3/origin/bdd3c3c3d814f974d45d9be460d5a66a.pnghttps://p.ananas.chaoxing.com/star3/origin/9013fc3411ac505abed248ac00a80d36.pnghttps://p.ananas.chaoxing.com/star3/origin/f675b4422c15e05748ebddd882faa308.pnghttps://p.ananas.chaoxing.com/star3/origin/3895cb15e5f52df4fab9f7a8ad29c794.png
- 设,其中;又 其中,试利用二重积分的几何意义说明与之间的关系./sqp/img?f=2f17fe58198a286af46cfbf48ec2d04d.files%2Fimage009.pnghttps://p.ananas.chaoxing.com/star3/origin/754ba804b45e87e6f578aa3617bebf06.png/sqp/img?f=2f17fe58198a286af46cfbf48ec2d04d.files%2Fimage011.png/sqp/img?f=2f17fe58198a286af46cfbf48ec2d04d.files%2Fimage012.pnghttps://p.ananas.chaoxing.com/star3/origin/c9d52b4692fa648970aeba85853ee9a0.png/sqp/img?f=2f17fe58198a286af46cfbf48ec2d04d.files%2Fimage014.png
- https://p.ananas.chaoxing.com/star3/origin/b31898e8d988e836116efe3cba9a910f.pnghttps://p.ananas.chaoxing.com/star3/origin/fb8dc50d75c1b761d9389a77bc20b4fd.pnghttps://p.ananas.chaoxing.com/star3/origin/7e75cd17522334f54b2eaedb009dba9a.png