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3 years ago

How to write the inverse of 3x+4y=12 in f^-1 (x)?

1 answer:

8 0

3x+4y=12

4y=12-3x

y=(12-3x)/4 <---------- This is f(x)

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

3x+4y=12

3x=12-4y

x=(12-4y)/3

Therefore:

f⁻¹(x)=(12-4x)/3

=[4(3-x)]/3

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A piece of wire 23 m long is cut into two pieces. One piece is bent into a square and the other is bent into an equilateral tria

goldfiish [28.3K]

Answer:

wire for square to maximize total area = 23 m

Wire to minimize total area = 2.019 m

Step-by-step explanation:

For the square, let's say the total length of the square is "y" m.

Thus, length of one side is = y/4

And area of the square = (y/4) = y²/16

Since the wire is 23 m, then total length of equilateral triangle is; 23 - y.

Thus, length of one side of equilateral triangle = (23 - y)/3

Using trigonometric ratio, we can find the height of the triangle and thus area.

Area of triangle = (√3)/4) × ((23 - y)/3)²

Area of triangle = (√3)/36)(23 - y)²

So, total area of square and triangle is;

A_total = (y²/16) + (√3)/36)(23 - y)²

Now, extremizing this function by derivatives, we have;

dA/dy = (y/8) - (√3)/18)(23 - y)

d²A/dy² = ⅛ + (√3)/18)

So, d²A/dy² > 0

Now,let's find the maximum or minimum of the function.

So, we equate dA/dy to zero.

Thus;

(y/8) - (√3)/18)(23 - y) = 0

y/8 = (√3)/18)(23 - y)

(y/8) + (√3)/18)y = 23((√3)/18)

Multiply through by 8 to give;

y + 0.0962y = 2.2132

1.0962y = 2.2132

y = 2.2132/1.0962

y = 2.019 m

2.019 will be a minimum because d²A/dy² > 0

The maximum will occur at a boundary of the allowed values. Thus, the absolute maximum is for y = 23.

Note that a square has more area than a triangle and as such it is normal for the square to get the largest area over the triangle and therefore we will have to use all of the wire to construct the square.

6 0

4 years ago

Solve for the unknown<br> 7(42x)=28(4x)

aalyn [17]

Try to use Mathway if your having trouble solving your equations

4 0

3 years ago

Read 2 more answers

Charlie is trying to cover the shape shown with paper. He will NOT be covering the top and the bottom. How much paper will he ne

DENIUS [597]

You need to determine how much paper you need to cover the lateral side of the cylinder shown in the picture. For this, you have to calculate the surface area of the cylinder, which you can do using the following formula:

$A=2\pi rh$

Where

A is the area

π is the number pi, for the calculations we usually use up to the first two decimal values of this number, 3.14

r is the radius

h is the height of the cylinder

The given cylinder has a height of h=15m and a diameter of d=6m

To calculate the lateral area you need to use the radius. The diameter is twice the radius, so to determine the radius of the cylinder you have to divide the diameter by 2