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finlep [7]
3 years ago
5

PRACTICE ANOTHER A piece of wire 18 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? m (b) How much wire should be used for the square in order to minimize the total area? m
Mathematics
1 answer:
sergejj [24]3 years ago
3 0

Answer:

Step-by-step explanation:

We have the equations

4x + 3y = 18   where x = the side of the square and y = the side of the triangle

For the areas:

A = x^2 + √3y/2* y/2

A = x^2  + √3y^2/4

From the first equation x = (18 - 3y)/4

So substituting in the area equation:

A = [ (18 - 3y)/4]^2 + √3y^2/4

A = (18 - 3y)^2 / 16 + √3y^2/4

Now for maximum / minimum area the derivative = 0 so we have

A' = 1/16 * 2(18 - 3y) * -3 + 1/4 * 2√3 y = 0

-3/8 (18 - 3y) + √3 y /2 = 0

-27/4 + 9y/8 + √3y /2 = 0

-54 + 9y + 4√3y = 0

y = 54 / 15.93

= 3.39 metres

So x = (18-3(3.39) / 4 = 1.96.

This is a minimum value for x.

So the total length of wire the square  for minimum  total area is 4 * 1.96

= 7.84 m

There is no maximum area as the equation for the total area is a quadratic with a positive leading coefficient.

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givi [52]
This is a geometric sequence with an initial term of 27 and a common ratio of 1/3

This just means that each term is 1/3 the term preceding it.

Any geometric sequence can be expressed as:

a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number in this case:

a(n)=27(1/3)^(n-1)
5 0
3 years ago
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A. 30 -1 =7<br> B.<br> 32 = 8<br> 1) How can we get Equation B from Equation A?
mixer [17]

Answer:

you +1 on each side

Step-by-step explanation:

a is 30-1=7

b is 32=8

to get from "a" to "b" you simply add one on both sides

32 - 1 = 7

+ 1 +1

------------------

32=8

6 0
3 years ago
plz help me and I kindly ask that u show work if possible? Plz don't answer if u don't know how to do the problem. PLZ help
soldier1979 [14.2K]

part A is just simple multiplication
since there are 2 6 sided number cubes there are 36 possible outcomes(6 sides *6 sides)

Part B is a little trickier. First off, you must find how to get seven.
1. 1+6 and 6+1

2. 2+5 and 5+2

3.3+4 and 4+3

therefore there are six combinations

you put that number over the total combos and get 6/36 or 1/6.

Hope this helps!

6 0
3 years ago
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Help please tell me what the answer is ASAP
Amiraneli [1.4K]

Answer:

The approximated length of EF is 2.2 units ⇒ A

Step-by-step explanation:

<em>The tangent ratio in the right triangle is the ratio between the opposite side to the adjacent side of one of the acute angle in the triangle</em>

In the given figure

∵ The triangle DFE has a right angle F

∵ The opposite side to angle D is EF

∵ The adjacent side to angle D is DF

→ By using the tangent ratio above

∴ tan(∠D) = \frac{EF}{DF}

∵ DF = 6 units

∵ m∠D = 20°

→ Substitute then in the ratio above

∴ tan(20°) = \frac{EF}{6}

→ Multiply both sides by 6

∴ 6 tan(20°) = EF

∴ 2.183821406 = EF

→ Approximate it to the nearest tenth

∴ 2.2 = EF

∴ The approximated length of EF is 2.2 units

7 0
3 years ago
Jennifer can clean her room 2 hours, while John can clean the same room in 5 hours. How many hours would it take for them to cle
True [87]
For 1 hour:
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7 0
3 years ago
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