Minimum & Maximum Cost

[nycmathguy]

Section 2.1
69 & 70

To find the minimum cost, I must evaluate C(-b/2a).

To find the maximum cost, I must evaluate P(-b/2a).

You say?

 

[MathLover1]

correct

 

[nycmathguy]

correct

How about that? Not too bad at all.

 

[nycmathguy]

correct

Question 69

-b/2a

-(-10)/2(0.25)

10/0.5 = 20

C = minimum cost

C = 800 - 10(20) + 0.25(20)^2

C = 800 - 200 + 100

C = 800 - 100

C = 700

The minimum cost is $700.

Question 70

-b/2a

-20/2(-0.5)

-20/-1 = 20

Let P = maximum profit

P = 230 + 20(20) - 0.5(20)^2

P = 230 + 400 -0.5(400)

P = 630 - 100

P = 530

The maximum profit is $530.

 

[MathLover1]

69 correct

70. correction
0.5(400)=200

P = 630 - 200=430
max{230 + 20 x - 0.5 x^2} = 430 at x = 20

 

[nycmathguy]

69 correct

70. correction
0.5(400)=200

P = 630 - 200=430
max{230 + 20 x - 0.5 x^2} = 430 at x = 20

Thank you for making question 70 clear. I am solving most questions on the overnight hours on my break time. It is very hard to answer math problems while trying to stay awake. If I don't do it this way, we will never finish the course.