AllExperts > Experts 
Search      

Calculus

Volunteer
Answers to thousands of questions
 Home · More Questions · Answer Library  · Encyclopedia ·
More Calculus Answers
Question Library

Ask a question about Calculus
Volunteer
Experts of the Month
Expert Login

Awards

About Us
Tell friends
Link to Us
Disclaimer

 
 
 
 
About Paul Klarreich
Expertise
All topics in first-year calculus including infinite series, max-min and related rate problems. Also trigonometry and complex numbers, theory of equations, exponential and logarithmic functions. I can also try (but not guarantee) to answer questions on Analysis -- sequences, limits, continuity.

Experience
I taught all mathematics subjects from elementary algebra to differential equations at a two-year college in New York City for 25 years.
 
   

You are here:  Experts > Teens > Homework/Study Tips > Calculus > Maximum-minimum problems

Topic: Calculus



Expert: Paul Klarreich
Date: 6/17/2008
Subject: Maximum-minimum problems

Question
After receiving $1000, you must carry out an intervention to increase the population of a marine mammal. You estimate that if M Gallons of medicine and N Gallons of nutrients are added to their marine habitat, then by next year this will save M^2+NM+12N lives. A Gallon of medicine costs $25 and a gallon of nutrients costs $5.
a) what is the cost of M gallons of medicine and N gallons of medicine?
b) To maximize within $ 1000, which combinations of medicine and nutrients would you put in the habitat?
C) which combination would you use? How many marine mammals would be saved by next year?

     I tried to do it as an expression of M so I kept M as medicine but made N= 1000 - M
--- I got stuck on how to actually write these two into the problem

Answer
Questioner:   Maxime
Category:  Calculus
Private:  No
 
Subject:  Maximization and Optimization
Question:  After receiving $1000, you must carry out an intervention to increase the population of a marine mammal. You estimate that if M Gallons of medicine and N Gallons of nutrients are added to their marine habitat, then by next year this will save M^2+NM+12N lives. A Gallon of medicine costs $25 and a gallon of nutrients costs $5.
a) what is the cost of M gallons of medicine and N gallons of medicine?
b) To maximize within $ 1000, which combinations of medicine and nutrients would you put in the habitat?
C) which combination would you use? How many marine mammals would be saved by next year?

    I tried to do it as an expression of M so I kept M as medicine but made N= 1000 - M
--- I got stuck on how to actually write these two into the problem
.....................................
Hi, Max, (OK to call you that?)

It looks as if your problem is:

Maximize  S = M^2 + MN + 12N,

subject to the 'constraint':

Cost = 25M + 5N = 1000  [not  M + N = 1000.  I think that is a mistake.]

Solve that for N in terms of M, in order to eliminate N and get S = f(M).

25M + 5N = 1000

5N = 1000 - 25M
N = 200 - 5M

Now S = M^2 + MN + 12N

S = M^2 + M(200 - 5M) + 12(200 - 5M)

S = M^2 + 200M - 5M^2 + 2400 - 60M

S =  - 4M^2 + 140M + 2400

Now differentiate:

dS/dM = - 8M + 140

Set that = 0:

M = 140/8 = 35/2 gallons

and  

N = 200 - 5M = 200 - 5(35/2) = 200 - 175/2 = 225/2 gal.

Finally, get S(M,N) for part c. [I'll leave that to you.]


Add to this Answer    Ask a Question



  Rate this Answer
   Was this answer helpful?
Not at allDefinitely              
   12345  

     
About Us | Advertise on This Site | User Agreement | Privacy Policy | Help
Copyright  © 2008 About, Inc. About and About.com are registered trademarks of About, Inc. The About logo is a trademark of About, Inc. All rights reserved.