homework+1

1、a company want to rent out a kind of TV, they have 40 TVs, and evey one mouth time is about 50 dollars, it will sold out. If every mouth add 5 dollars, it will lose one to rent out, but every TV is doesn't rent out, the other money need to pay for it is about 10 dollars, if the tent is x, every mouth profit is y, what the relationship between x and y? 2、people want to built a bridge, but they need to creat a safe radian 3、use a line L to make a square or cirle, which one area is bigger？ 4、to throw a ball, how to find the radian about the balla？ 5、in hospital, the electrocardiogram is a kind of function