A piece of wire 13 m long is cut into two pieces. One piece is bent into a square and the other is bent into an equilateral triangle. (a) How much wire should be used for the square in order to maximize the total area? (b) How much wire should be used for the square in order to minimize the total area?

The function you seek to minimize is

()=3‾√4(3)2+(13−4)2

f

(

x

)

=

3

4

(

x

3

)

2

+

(

13

−

x

4

)

2

Then

′()=3‾√18−13−8=(3‾√18+18)−138

f

′

(

x

)

=

3

x

18

−

13

−

x

8

=

(

3

18

+

1

8

)

x

−

13

8

Note that ″()>0

f

″

(

x

)

>

0

so that the critical point at ′()=0

f

′

(

x

)

=

0

will be a minimum. The critical point is at

=1179+43‾√≈7.345m

x

=

117

9

+

4

3

≈

7.345

m

So that the amount used for the square will be 13−

13

−

x

, or

13−=524+33‾√≈5.655m

step-by-step explanation:

if you want to solve percent error follow these steps.

1. subtract the accepted value from the experimental value.

2. take the absolute value of step 1.

3. divide that answer by the accepted value.

4. multiply that answer by 100 and add the % symbol to express the answer as a percentage.

if you want to solve percent of change just do this.

1. work out the difference (increase) between the two numbers you are comparing.

2. divide the increase by the original number and multiply the answer by 100. if your answer is a negative number then this is a percentage decrease.

hope this : )