物业管理都门每月都要去居民家查电表，电表读数与上次读数的差就是这段时间内用点亮（度）；己知小亮家所在的小区每度的电费为0.55元．上月初小亮家电表显示的读数为300 （度）；如果全月的电费为y元，本月初小明家电表的读数为x（度）；
①写出y与x之间的关系式；
②本月初物业部门收取了小亮家50.6 元电费；试求出本月初小明家电表的读数？
③估算一下小明家上个月平均每天的用电量是多少？
解：①∵小亮家所在的小区每度的电费为0.55元．
上月初小亮家电表显示的读数为300 （度），
∴y=0.55（x﹣300）=0.55x﹣165；
②∵本月初物业部门收取了小亮家50.6 元电费；
∴50.6=0.55x﹣165；解得：x=392，
∴本月初小明家电表的读数为392．
③∵小明家上月用电量为：392﹣300=92度，
∴92÷30≈3度，
∴估算一下小明家上个月平均每天的用电量是3度．
| At the public radio station KEXP in Seattle, there’s a simple procedure for evaluating new technology. "We just go ahead and do stuff," says one of the station’s morning disc jockeys. That’s how the quirky station created one of the first music podcasts—without support from major record companies. A podcast is a digital recording of a radio-style audio program that can be downloaded from the Internet and played on a digital music player. Many podcasters think the technology could revolutionize radio as TiVo did television. Podcasting is a great way for KEXP to reach thousands of new listeners, especially those outside of Seattle. But the station can’t podcast programs such as John in the morning—a variety of independent and mainstream music—because record companies haven’t provided an easy, affordable way for podcasters to license songs. That’s why most podcasts today are talk radio. KEXP decided that it couldn’t sit around and wait and wait for a major label to sign off on this. So it invited 14 unsigned or small bands from the Seattle area to contribute songs to a podcast. The station asked a lawyer—a listener who volunteers at the station—to draw up a simple contract for the bands. KEXP did not release numbers but said the podcast was a hit. KEXP is now podcasting some live performances to which it owns the rights. Since podcasts are recordings, they can be played at any time. Listeners can pause, fast-forward or rewind them. And since podcasts are posted online, listeners can download programs from radio stations and independent broadcasters from all over the world. The podcasts can also be hacked and pirated. An enterprising listener could pull songs out of a podcast and turn them into music files or CDs. That’s why many record companies say the technology is promising but problematic. But record labels worry that listeners will pirate the songs contained in the downloaded radio shows. For example, OK Go and several other emerging bands with EMI have their own podcasts. But EMI is not ready to approve a blanket podcasting license. "Podcasting is potentially very exciting," says Executive Vice-president Adam Klein. The result: yet another Napster-like standoff over piracy and music rights. |
A "disk jockey" is most possibly a ______ .
A．disk playing device
B．joker playing disks
C．broadcasting worker
D．hockey player on radio