题目

Tell your car to make a phone call without holding the phone．Tell your car to send an e-mail without touching the computer or even tell your car to send a call for help．Sound like something from a science fiction（科幻）movie．Well, thanks to a new talking car , this is soon to become reality． Road Track．the Israeli（以色列）producer of Chevrolet（雪弗莱）, has built a computer platform called Chevy Star．It offers the driver a wide range of things you can get with your voice． It uses a box the size of a mobile phone attached to（贴到）the rear view mirror（后8．已知圆的方程是x2+y2=4，求经过圆上一点M（$\sqrt{2}$，$\sqrt{2}$）的切线方程．