3g+h=18 2g+3h=26 what is g and what is h

An open metal tank of square base has a volume of 123 m^3

snow_lady [41]

Answer:

a) h = 123/x^2

b) S = x^2 +492/x

c) x ≈ 6.27

d) S'' = 6; area is a minimum (Y)

e) Amin ≈ 117.78 m²

Step-by-step explanation:

a) The volume is given by ...

V = Bh

where B is the area of the base, x^2, and h is the height. Filling in the given volume, and solving for the height, we get:

123 = x^2·h

h = 123/x^2

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b) The surface area is the sum of the area of the base (x^2) and the lateral area, which is the product of the height and the perimeter of the base.

$S=x^2+Ph=x^2+(4x)\dfrac{123}{x^2}\\\\S=x^2+\dfrac{492}{x}$

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c) The derivative of the area with respect to x is ...

$S'=2x-\dfrac{492}{x^2}$

When this is zero, area is at an extreme.

$0=2x -\dfrac{492}{x^2}\\\\0=x^3-246\\\\x=\sqrt[3]{246}\approx 6.26583$

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d) The second derivative is ...

$S''=2+\dfrac{2\cdot 492}{x^3}=2+\dfrac{2\cdot 492}{246}=6$

This is positive, so the value of x found represents a minimum of the area function.

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e) The minimum area is ...

$S=x^2+\dfrac{2\cdot 246}{x}=(246^{\frac{1}{3}})^2+2\dfrac{246}{246^{\frac{1}{3}}}=3\cdot 246^{\frac{2}{3}}\approx 117.78$

The minimum area of metal used is about 117.78 m².

3 0

3 years ago

SOMEONE PLEASE HELP ITS WORTH 90 POINTS

motikmotik

Answer:

Step-by-step explanation:

The two x angles on the right are supplementary which means they add up to 180 degrees

5x + 12 + 7x - 24 = 180

12x - 12 = 180

12x = 192

x = 192/12

x = 18

5x + 12 and y are corresponding angles and are therefore equal

5(18) + 12 = 90 + 12 = 102

Therefore y = 102

3 0

3 years ago

Approximate <img src="https://tex.z-dn.net/?f=-8%20%2B%5Csqrt%7B20%7D" id="TexFormula1" title="-8 +\sqrt{20}" alt="-8 +\sqrt{20}

alisha [4.7K]

The value of the radical expression -8 + √20 when expanded and solved is -3.6, based on the given parameters

<h3>What are equivalent expressions?</h3>

Equivalent expressions are different expressions that have equal values when evaluated and compared

<h3>How to approximate the radical expression?</h3>

The expression is given as:

-8 + √20

The above expression is a radical expression

So, we start by doing the following

Express 20 as 5 * 4

-8 + √20 = -8 + √(5 * 4)

Split the radical expression √(5 * 4)

-8 + √20 = -8 + √5 * √4

Evaluate the square root of 4 i.e. √4 = 2

-8 + √20 = -8 + √5 * 2

This gives

-8 + √20 = -8 + 2√5

Evaluate the square root of 5

-8 + √20 = -8 + 2 * 2.2

Evaluate the product of 2 and 2.2

-8 + √20 = -8 + 4.4

Evaluate the difference

-8 + √20 = -3.6

Based on the given parameters, the value of the radical expression -8 + √20 when expanded and solved is -3.6

So, the complete equation is:

-8 + √20 = -3.6