Economists usually call an industry an oligopoly if .

a. the four largest firms produce at least 70–80 percent of the output

b. only one product is available on the market

c. here is one firm that produces 100 percent of the output

d. the ten largest firms produce less than 50 percent of the output

Answerfriction

The answer is    (d) 7/2======we have    we also  have an integral      notice how function f splits up at x = 0. there's a left piece and a right pieceso we'll need to do the same thing with our integral: split it at x = 0we use a property of integrals that allows us to split up and sum:     notice that for the piecewise function f, the function has the equationf(x) = x when x  ≤ 0. so for the integral  , f(x) = x so it changes into      for the piecewise function f, the function has the equationf(x) = x+1  when x  > 0. for the integral  , we have    therefore, back to our splitted integral: