Name______________________

 

Quiz 1 – Chapter P

  1. Find all intercepts for the graph: x = y3 - 2y.

    2. To find the x-intercepts, set y=0. So x=03+2(0)=0, and x=0 is the x-intercept.

    To find the y-intercepts, set x=0. So 0= y3 -2y, and y=0, y = ± Ö 2 are the y-intercepts.

     

     

  2. Let f(x)= x2 - 4 and g(x) = (x-1)/Ö (x-5). Find the following:
  1. f(4); 42 - 4 = 12
  2. f(3a); (3a)2 - 4 = 9a2 - 4
  3. f o g (x); f[(x-1)/Ö (x-5)] = (x-1)2/(x-5) - 4
  4. [f(x + h) – f(x)]/h = [(x+h)2-4 - (x2 - 4)]/h = [x2+2xh+h2 - 4 - (x2 - 4)]/h = 2x+h

 

 

  1. Find the domain for the function g(x) above.

We can't divide by 0, so Ö (x-5) ¹ 0 means x ¹ 5. Also we have x-5 ³ 0 because of the radical. Therefore the domain is x > 5.

(4) In 1999 the average Major League baseball salary was $1,990,000. In 1997, the average salary was $1,330,000. Suppose that the relationship between time and salary is linear. What was the average salary for Major League players in 1979? Does your answer make sense?

 

We have two points on the line, (1999, 1,990,000) and (1998, 1,330,000). The slope is

computed as (1,330,000-1,990,000)/ (1997-1999) = 330,000. Therefore in 1979, twenty years before 1999, the average salary would be 1,990,000 - 20(330,000)= -$4,610,000. Of course this is absurd, as no salary would be negative. This shows that this linear model stinks.