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2 years ago

How many real solutions x^2+x-30=0?

Mathematics

1 answer:

VashaNatasha [74]2 years ago

8 0

Answer:

The final solution is all the values that make (x-6)(x+5)=0 true.

x=6, -5

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A programmer plans to develop a new software system. In planning for the operating system that he will use, he needs to estimat

Vedmedyk [2.9K]

Using the z-distribution, we have that:

a) A sample of 601 is needed.

b) A sample of 93 is needed.

c) A. Yes, using the additional survey information from part (b) dramatically reduces the sample size.

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which z is the z-score that has a p-value of $\frac{1+\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

95% confidence level, hence $\alpha = 0.95$ , z is the value of Z that has a p-value of $\frac{1+0.95}{2} = 0.975$ , so $z = 1.96$ .

For this problem, we consider that we want it to be within 4%.

Item a:

The sample size is <u>n for which M = 0.04.</u>

There is no estimate, hence $\pi = 0.5$

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.04 = 1.96\sqrt{\frac{0.5(0.5)}{n}}$

$0.04\sqrt{n} = 1.96\sqrt{0.5(0.5)}$

$\sqrt{n} = \frac{1.96\sqrt{0.5(0.5)}}{0.04}$

$(\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.5(0.5)}}{0.04}\right)^2$

$n = 600.25$

Rounding up:

A sample of 601 is needed.

Item b:

The estimate is $\pi = 0.96$ , hence:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.04 = 1.96\sqrt{\frac{0.96(0.04)}{n}}$

$0.04\sqrt{n} = 1.96\sqrt{0.96(0.04)}$

$\sqrt{n} = \frac{1.96\sqrt{0.96(0.04)}}{0.04}$

$(\sqrt{n})^2 = \left(\frac{1.96\sqrt{0.96(0.04)}}{0.04}\right)^2$

$n = 92.2$

Rounding up:

A sample of 93 is needed.

Item c:

The closer the estimate is to $\pi = 0.5$ , the larger the sample size needed, hence, the correct option is A.

For more on the z-distribution, you can check brainly.com/question/25404151

8 0

2 years ago

Estimate the slope of the tangent line of the function y(t)=\sqrt{(3t+1} at the point t=2.

Korvikt [17]

Answer: 0.567

Step-by-step explanation:

$y(t)=\sqrt{3t+1} \\\\y'(t)=\dfrac{3}{2\sqrt{3t+1} } \\\\y'(2)=\dfrac{3}{2\sqrt{3*2+1} } =\dfrac{3\sqrt{7} }{14} =0,56694670951384084082177480435127\approx{0.567}$

7 0

2 years ago

Which classification best represents a triangle with side lengths 6 cm, 10 cm, and 12 cm?

DedPeter [7]

Answer:

obtuse because 62 + 102 < 122

3 0

1 year ago

Read 2 more answers

Urban rail systems have been proposed to alleviate traffic congestion, but results in many cities have been cited as evidence th

BartSMP [9]

Answer:

C) fails to consider that commuting trips may cause significantly more than 20 percent of the traffic congestion

Step-by-step explanation:

The correct option is - C) fails to consider that commuting trips may cause significantly more than 20 percent of the traffic congestion

Reason -

Option A is incorrect because the statistics can not be incorrect.

Option B is incorrect because they are not talking about the city.

Option C is correct because Urban rail reduces congestion.

Option D is incorrect because the opposers cited the example of one city and the supporters are presenting evidence in the case of that city itself.

Option E is incorrect because they are providing an explanation for why the commuters data given by opposers is not relevant. The opposers talked about commuters.

5 0

2 years ago

How to divide 9 by 3960.0

aleksandr82 [10.1K]

3936/9=440 if that is what you meant

5 0

3 years ago

Read 2 more answers