Please help me!
asked Apr 24, 2013 in Calculus Answers by anonymous

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

2 Answers

for rektangel, square hav max area

leng+wide=78, so leng=wide=39

answered Apr 24, 2013 by anonymous
Fisrt let's formulate an equation based on what the word problem is giving us.

The lenght and width of a rectangle have a sum of 78= L + W=78

Then it's asking what dimensions give the maximum area, so you must know your Area equation=

A= L(W)




Now plug this into your area equation

A= (78-W) (W)


Now a very interesting concept can be applied, we need to take the derivative of this equation, and must set A= 0.

0= 78(1)-2W

*The (1) came to be because the derivative of a variable is 1. W^2 was changed to 2w because of the power rule of derrivatives, thsis sttes that  we can  bring out the power in front of the variable and subtract 1 from the exponent so we get 2w^1 which is 2W*

Now move things around and solve for W:



Now plug in value back into the L=78-W equation to solve for L

L= 78- 39


Hope this Helps :)
answered Jul 27 by Priscila Love God & Virgin Mary

Related questions

Welcome to, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
81,780 questions
86,085 answers
69,588 users