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3 years ago

Select the solution(s) of the original equation. 3+ √21/2+4 3+ √21/2-4 3- √21/2+4 3-√21/2-4

Mathematics

2 answers:

jarptica [38.1K]3 years ago

4 0

Answer:

2nd and 4th on edg

Step-by-step explanation:

3+21pi / 2 +4

3-21pi / 2 -4

frez [133]3 years ago

4 0

Answer:

B and D

Step-by-step explanation:

Correct on Edge

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A firework is fired into the air from the top of a barn. Tis hight (h) above the ground in yards after (t) seconds is given by t

Grace [21]

The given function for the height of the firework is a quadratic function

1. Time at which the firework reaches the maximum height is 1 seconds

2. The maximum height of the firework, is 25 yards

3. Time after which the firework will fall to the ground is (1 + √5) seconds

Reason:

The given function that represents the height of the fireworks with time is

presented as follows;

h(t) = -5·t² + 10·t + 20

1. The time at which the firework reaches its maximum height is given by

the maximum point of the given function as follows;

The x-value of the maximum point of a quadratic function is $x = \dfrac{b}{2 \cdot a}$

Where;

a, and b, are the coefficient of x² and x, in the general form of a quadratic function f(x) = a·x² + b·x + c

By comparison, we have;

$t = -\dfrac{10}{2 \times (-5)} = 1$

The time at which the firework reaches the maximum height is t = 1 seconds

2. The maximum height is given by plugging in the value of t, at the maximum point into the given function as follows;

h(1) = -5×1² + 10×1 + 20 = 25

The maximum height of the firework, f(1) = 25 yards

3 The time at which the firework will fall to the ground, is given by the zero of the function as follows;

When the firework falls to the ground, h(t) = 0 = -5·t² + 10·t + 20

Dividing both sides by (-5) gives;

$\dfrac{0}{-5} = \dfrac{ -5 \cdot t^2 + 10 \cdot t + 20}{-5} = t^2 - 2 \cdot t - 4$

t² - 2·t - 4 = 0

By the quadratic formula $x = \dfrac{-b\pm \sqrt{b^{2}-4\cdot a\cdot c}}{2\cdot a}$ , we get;

$t = \dfrac{2\pm \sqrt{(-2)^{2}-4\times 1\times (-4)}}{2\times 1} = \dfrac{2\pm \sqrt{20}}{2\times 1} = \dfrac{2\pm 2 \times \sqrt{5}}{2\times 1} = 1 \pm \sqrt{5}$

Therefore;

The time after which the firework will fall to the ground, t = 1 + √5 seconds

Learn more here:

brainly.com/question/20628403

3 0

3 years ago

5. Many samples of the same size are taken from a population with a population proportion of 0.75. Which sample

antoniya [11.8K]

Answer:

18.

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n(n being at least 30), the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

In this question:

n has to be at least 30. So the choice that answer this question, a size of n too small to use a normal curve to approximate the sampling distribution, is 18.

8 0

3 years ago

Write an expression to find the perimeter of the rectangle below:

taurus [48]

Answer:

the expression is (4x+2-x) * 2 =

Step-by-step explanation:

Write an expression to find the perimeter of

the rectangle below:

rectangle perimeter = (w + l) *2

(4x+2-x) * 2 =

3 0

2 years ago

How do I write an algebraic equation for this word problem?

Doss [256]

Hi.

Please note that I haven't done much algebra.

4 more = 4 +

Twice as many than the runner up means 2 times the amount they ate (a variable) = 2n

So far we have 4 + 2n

Since it's an equation, we are going to know what it equals. In the problem, we find out that it's 11. So the equation looks like this:

4 + 2n = 11

If this didn't work out, please let me know.

~

I believe n = 3.5

7 0

3 years ago

Help I don't understand I need the answer wuick

aksik [14]

Answer is 14 I think pretty sure hope so yeah

6 0

3 years ago

Select the solution(s) of the original equation. 3+ √21/2+4 3+ √21/2-4 3- √21/2+4 3-√21/2-4​

Select the solution(s) of the original equation. 3+ √21/2+4 3+ √21/2-4 3- √21/2+4 3-√21/2-4