设
且当x=0时，z=siny；当y=0时，z=sinx，则z(x，y)=______.

Digital photography is still new enough that most of us have yet to form an opinion about it (1) develop a point of view. But this hasn’t stopped many film and computer fans from agreeing (2) the early conventional wisdom about digital cameras — they’re neat (3) for your PC, but they’re not suitable for everyday picture taking.

The fans are wrong. More than anything else, digital cameras are radically (4) what photography means and what it can be. The venerable medium of photography (5) we know, it is beginning to seem out of (6) with the way we live. In our computer and camcorder (7) , saving pictures as digital (8) and watching them on TV is no less practical — and in many ways more (9) than fumbling with rolls of film that must be sent off to be (10) .

Paper is also terribly (11) . Pictures that are incorrectly framed, (12) , or lighted are nonetheless committed to film and ultimately processed into prints.

The digital medium changes the (13) . Still images that are (14) digitally can immediately be shown on a computer (15) , a TV screen, or a small liquid crystal display (LCD) built right into the camera. And since the points of light that (16) an image are saved as a series of digital bits in electronic memory, (17) being permanently etched onto film, they can be erased, retouched, and transmitted (18) .

What’s it like to (19) with one of these digital cameras It’s a little like a first date — exciting, confusing and fraught with (20) .

在上世纪80年代中期，最常用的内部路由协议是路由信息协议 (60) ，它执行 (61) 。当网络规模扩大时，该算法使得传送的路由信息太多，增加了网络负载，后来又出现了执行最短路径优先算法的ICP。按照这种协议，每个路由器向网络中的其他路由器发布 (62) ，当路由信息改变后，路由器按照 (63) 算法更新路由表。在不同自治系统的路由器之间，运行外部网关协议EGP，典型的EGP是 (64) 。

硬盘

软盘

RAM

ROM

x1=2 y1=2 x2=2 y2=1

x1=2 y1=2 x2=2 y2=2

x1=2 y1=1 x2=2 y2=2

x1=2 y1=1 x2=2 y2=1

购买权

收益权

否决权

优先购买权

A、错误

B、正确