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Anastaziya [24]
2 years ago
9

HELP When does expanding and simplifying a(b + c) result in a positive value for ac?

Mathematics
1 answer:
Reil [10]2 years ago
7 0

Answer:

When c and a are positive or both are negative

Step-by-step explanation:

negative times negative equals positive so if a was negative and c was negative -a*-c= ac

Of course positive times positive equals negative so if a and c were positive we could do

a*c= ac

Hope I could help !

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In the figure below ABCD is a rectangle and DA and CB are radii of circles tangent externally, AB = 4 cm. Provide the answer in
ad-work [718]

Answer:

a. Radius of DA - 2 cm.

b. Area of rectangle ABCD -

c. Area of shaded - 8-4π

d. Perimeter of shaded region - also 8-4π

<em><u>Hope this helps!  </u></em>

3 0
3 years ago
Mrs. Giuntini’s lawn is triangle shaped with a base of 25 feet and a height of 10 feet. What is the area of Mrs. Giuntini’s lawn
Vedmedyk [2.9K]

area \:  =  \frac{1}{2} bh \\ area \:  =  \frac{1}{2} (25)(10) \\ area =  \frac{1}{2} 250 \\ area = 125 \: feet ^{2}

4 0
3 years ago
Read 2 more answers
Confidence Interval Mistakes and Misunderstandings—Suppose that 500 randomly selected recent graduates of a university were as
kvv77 [185]

Answer:

The correct 95% confidence interval is (8.4, 8.8).

Step-by-step explanation:

The information provided is:

n=500\\\bar x=8.6\\\sigma=2.2

(a)

The (1 - <em>α</em>)% confidence interval for population mean (<em>μ</em>) is:

CI=\bar x\pm z_{\alpha/2}\times \frac{\sigma}{\sqrt{n}}

The 95% confidence interval for the average satisfaction score is computed as:

8.6 ± 1.96 (2.2)

This confidence interval is incorrect.

Because the critical value is multiplied directly by the standard deviation.

The correct interval is:

8.6\pm 1.96 (\frac{2.2}{\sqrt{500}})=8.6\pm 0.20=(8.4,\ 8.6)

(b)

The (1 - <em>α</em>)% confidence interval for the parameter implies that there is (1 - <em>α</em>)% confidence or certainty that the true parameter value is contained in the interval.

The 95% confidence interval for the mean rating, (8.4, 8.8) implies that the true there is a 95% confidence that the true parameter value is contained in this interval.

The mistake is that the student concluded that the sample mean is contained in between the interval. This is incorrect because the population is predicted to be contained in the interval.

(c)

The (1 - <em>α</em>)% confidence interval for population parameter implies that there is a (1 - <em>α</em>) probability that the true value of the parameter is included in the interval.

The 95% confidence interval for the mean rating, (8.4, 8.8) implies that the true mean satisfaction score is contained between 8.4 and 8.8 with probability 0.95 or 95%.

Thus, the students is not making any misinterpretation.

(d)

According to the Central Limit Theorem if we have a population with mean <em>μ</em> and standard deviation <em>σ</em> and we take appropriately huge random samples (<em>n</em> ≥ 30) from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.

In this case the sample size is,

<em>n </em>= 500 > 30

Thus, a Normal distribution can be applied to approximate the distribution of the alumni ratings.

7 0
3 years ago
How to evaluate 164​
Pepsi [2]

Answer:

164=82+82 or 164=82 x 2

Step-by-step explanation:

Hope that works

7 0
3 years ago
Evaluate the integral of the quotient of the cosine of x and the square root of the quantity 1 plus sine x, dx.
VMariaS [17]

Answer:

∫((cos(x)*dx)/(√(1+sin(x)))) = 2√(1 + sin(x)) + c.

Step-by-step explanation:

In order to solve this question, it is important to notice that the derivative of the expression (1 + sin(x)) is present in the numerator, which is cos(x). This means that the question can be solved using the u-substitution method.

Let u = 1 + sin(x).

This means du/dx = cos(x). This implies dx = du/cos(x).

Substitute u = 1 + sin(x) and dx = du/cos(x) in the integral.

∫((cos(x)*dx)/(√(1+sin(x)))) = ∫((cos(x)*du)/(cos(x)*√(u))) = ∫((du)/(√(u)))

= ∫(u^(-1/2) * du). Integrating:

(u^(-1/2+1))/(-1/2+1) + c = (u^(1/2))/(1/2) + c = 2u^(1/2) + c = 2√u + c.

Put u = 1 + sin(x). Therefore, 2√(1 + sin(x)) + c. Therefore:

∫((cos(x)*dx)/(√(1+sin(x)))) = 2√(1 + sin(x)) + c!!!

4 0
3 years ago
Read 2 more answers
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