已知:△ABC的两边AB、AC的长是关于x的一元二次方程x2-(2k+3)x+k

题型:解答题

问题:

已知:△ABC的两边AB、AC的长是关于x的一元二次方程x2-(2k+3)x+k2+3k+2=0的两个实数根,第三边BC的长为5.

(1)k为何值时,△ABC是以BC为斜边的直角三角形?

(2)k为何值时,△ABC是等腰三角形?并求△ABC的周长.

考点:一元二次方程的解法
题型:解答题

Travelling has been popular with people for a long time. Many of today’s travellers are trying to find an unusual experience or adventure. Hiking may be a good choice.

Instead of spending your vacation on a bus, in a hotel or sitting on the beach, you may want to try hiking. Hiking is a great way to travel. You will get close to nature and take exercise at the same time. Hiking is easy to do and doesn’t have to be very expensive. You can hike close to home or travel to other places. The basic equipment you need for hiking is simple: good shoes, clothes and a backpack. You can hike in the mountain, in a forest or along a river. You can also go for a hike in the city.

Hiking is fun and exciting, but you shouldn’t forget safety. Here are some basic tips for successful hiking:

﹡Don’t hike alone.

﹡ bring water, a good map and a cellphone.

﹡Wear a hat to protect yourself from the sun.

小题1: Hiking is a good way to get close to nature.

小题2: Good shoes, clothes and a backpack are the basic equipment for hiking.

小题3: People can only hike in the mountain, in a forest or along a river.

小题4: Hiking is always fun, exciting and safe

小题5: You’d better go hiking with others.

题型:解答题

下列哪些与哮喘气流受限机制有关()

A.支气管平滑肌收缩

B.支气管壁水肿

C.管腔内黏液栓阻塞

D.气道壁重塑

E.肺泡过度充气

题型:解答题

以下对化妆品定义的理解,哪个是正确的()。

A.化妆品只限于用涂、喷、洒或其它类似方法,施于人体表面的产品

B.化妆品是用来清洁、消除不良气味、护肤、美容和修饰目的的产品

C.按照化妆品的定义,任何可用涂、喷、洒或其它类似方法,施于人体表面的产品

D.按照化妆品的定义,任何可以达到美容目的的产品均是化妆品

E.按照化妆品的定义,清洁口腔黏膜等的产品属化妆品

题型:解答题

国家秘密技术出口,由申请单位或个人按照行政隶属关系报省、自治区、直辖市、计划单列市科技工作主管部门审查后,报科技部审批的是()。

A、秘密级技术

B、机密级技术

C、绝密级技术

D、各类秘密技术

题型:解答题

当用增量编程GOO指令时,U,W后面的数值是()点与目标点之间的距离与方向。

A.零点

B.当前

C.已知

D.未知

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