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3 years ago

20 points!!!Please help HURRY!!!

Mathematics

1 answer:

navik [9.2K]2 years ago

5 0

Answer:

Definitely not!

Step-by-step explanation:

It was reflected across the x axis, resized and moved in x and y directions, but since the shape ABCD is symmetrical across the y axis, a reflection across y axis won’t change anything!

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The length of a rectangular carpet is 4 feet greater than twice its width. If the area is 48 square feet, find the carpet’s leng

Sonbull [250]

l = 2w + 4

l * w = 48

We can substitute l with its value:

2w + 4 * w = 48

2w^2 + 4w - 48 = 0

2(w^2 + 2w - 24) = 0

2(w+6)(w-4) = 0

w = {4, -6}

5 0

3 years ago

A study was conducted to determine whether magnets were effective in treating pain. The values represent measurements of pain us

Zanzabum

Answer:

Step-by-step explanation:

Hello!

The objective of the study is to determine whether the magnets are effective in treating pain. For these two independent groups of individuals with equal affections were randomly sampled, one was treated with magnets and the other group of individuals, call it control group, was treated with a placebo treatment.

The information for both samples is:

X₁: pain measurement using a visual analog scale after the individual received magnet treatments.

X₁~N(μ₁;σ₁²)

n₁= 20

X[bar]₁= 0.46

S₁= 0.93

X₂: pain measurement using a visual analog scale of an individual of the control groups.

X₂~N(μ₂;σ₂²)

n₂= 20

X[bar]₂= 0.41

S₂= 1.26

The claim is that the pain reductions of the control group have more variation than the pain reductions of the target group. If it's so then we could suspect that the population variance of the control group, σ₂², will be greater than the population variance of the magnet group, σ₁².

To test the relationship between these two population variances you have to conduct a variance ratio test using the Snedecors F statistic.

The hypotheses are:

H₀: σ₂² ≤ σ₁²

H₁: σ₂² > σ₁²

α: 0.05

$F= (\frac{S_2^2}{S_1^2}) * (\frac{Sigma_2^2}{Sigma_1^2} )~~ F_{(n_2-1);(n_1-1)}$

This hypothesis test is one-tailed to the right, there is only one critical value:

$F_{(n_2-1);(n_1-1); 1 - \alpha } = F_{19;19; 0.95}= 2.17$

The decision rule for the test is:

If $F_{H_0}$ ≥ 2.17, then the decision is to reject the null hypothesis.

If $F_{H_0}$ < 2.17, then the decision is to not reject the null hypothesis.

$F_{H_0}= \frac{S_2^2}{S_1^2}*\frac{Sigma_2^2}{Sigma_1^2} = \frac{(1.26)^2}{(0.93)^2} * 1$

$F_{H_0} = 1.835 = 1.84$

Since the calculated value of F is less than the critical value, the decision is to reject the null hypothesis. So using a 5% significance level the decision is to not reject the null hypothesis, you can conclude that the population variance of the pain reduction of the control group is less or equal than the population variance of the pain reduction on individuals treated with magnets.

I hope it helps!

3 0

3 years ago

A track star runs two races on a certain day. The probability thathe wins the first race is 0.7, the probability that he wins th

NARA [144]

Answer:

a) 80% probability that he wins at least one race.

b) 30% probability that he wins exactly one race.

c) 20% probability that he wins neither race.

Step-by-step explanation:

We solve this problem building the Venn's diagram of these probabilities.

I am going to say that:

A is the probability that he wins the first race.

B is the probability that he wins the second race.

C is the probability that he does not win any of these races.

We have that:

$A = a + (A \cap B)$

In which a is the probability that he wins the first race but not the second and $A \cap B$ is the probability that he wins both these races.

By the same logic, we have that:

$B = b + (A \cap B)$

The probability that he wins both races is 0.5.

This means that $A \cap B = 0.5$

The probability that he wins the second race is 0.6

This means that $B = 0.6$

$B = b + (A \cap B)$

$0.6 = b + 0.5$

$b = 0.1$

The probability that he wins the first race is 0.7.

This means that $A = 0.6$

$A = a + (A \cap B)$

$0.7 = a + 0.5$

$a = 0.2$

A) he wins at least one race.

This is

$P = a + b + (A \cap B) = 0.2 + 0.1 + 0.5 = 0.8$

There is an 80% probability that he wins at least one race.

B) he wins exactly one race.

This is

$P = a + b = 0.2 + 0.1 = 0.3$

There is a 30% probability that he wins exactly one race.

C) he wins neither race

Either he wins at least one race, or he wins neither. The sum of these probabilities is 100%.

From a), we have that there is an 80% probability that he wins at least one race.

So there is a 100-80 = 20% probability that he wins neither race.

6 0

3 years ago

Evaluate the following limit:

Makovka662 [10]

If we evaluate the function at infinity, we can immediately see that:

$\large\displaystyle\text{$\begin{gathered}\sf \bf{\displaystyle L = \lim_{x \to \infty}{\frac{(x^2 + 1)^2 - 3x^2 + 3}{x^3 - 5}} = \frac{\infty}{\infty}} \end{gathered}$}$

Therefore, we must perform an algebraic manipulation in order to get rid of the indeterminacy.

We can solve this limit in two ways.

By comparison of infinities:

We first expand the binomial squared, so we get

$\large\displaystyle\text{$\begin{gathered}\sf \displaystyle L = \lim_{x \to \infty}{\frac{x^4 - x^2 + 4}{x^3 - 5}} = \infty \end{gathered}$}$

Note that in the numerator we get x⁴ while in the denominator we get x³ as the highest degree terms. Therefore, the degree of the numerator is greater and the limit will be \infty. Recall that when the degree of the numerator is greater, then the limit is \infty if the terms of greater degree have the same sign.

Dividing numerator and denominator by the term of highest degree:

$\large\displaystyle\text{$\begin{gathered}\sf L = \lim_{x \to \infty}\frac{x^{4}-x^{2} +4 }{x^{3}-5 } \end{gathered}$}\\$

$\ \ = \lim_{x \to \infty\frac{\frac{x^{4} }{x^{4} }-\frac{x^{2} }{x^{4}}+\frac{4}{x^{4} } }{\frac{x^{3} }{x^{4}}-\frac{5}{x^{4}} } }$

$\large\displaystyle\text{$\begin{gathered}\sf \bf{=\lim_{x \to \infty}\frac{1-\frac{1}{x^{2} } +\frac{4}{x^{4} } }{\frac{1}{x}-\frac{5}{x^{4} } } \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ =\frac{1}{0}=\infty } \end{gathered}$}$

Note that, in general, 1/0 is an indeterminate form. However, we are computing a limit when x →∞, and both the numerator and denominator are positive as x grows, so we can conclude that the limit will be ∞.

5 0

2 years ago

Pls help in this aaaaaa

ivanzaharov [21]

The question is incorrect. X is not defined UNLESS the hexagon is a regular hexagon, which means that all sides are equal (given) AND all angles are equal (not given).

Error in question aside, and ASSUMING the hexagon is regular, you can apply the principle that
1. the sum of exterior angles of ANY polygon is 360.
2. the sum of exterior angles and interior angles at EACH vertex is 180.
3. Multiply sum from (2) above by the number of vertices and subtract 360 gives the sum of the interior angles.
4. IF the polygon is regular (all angles equal), then each interior angle equals the result from (3) divided by n, the number of vertices.

Example for a regular heptagon (7 sides, 7 verfices).
1. Sum of exterior angles = 360
2. sum of interior and exterior angles at EACH vertex=180
3. multiply 180 by 7, subtract 360
180*7-360=900
4. since heptagon is regular, each interior angle equals 900/7=128.57 deg.

8 0

3 years ago