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3 years ago

10

A circle is centered at the point (-7, -1) and passes through the point (8, 7). The radius of the circle is 13 units. The point

(-15, y ) lies on this circle.
find Y

1 answer:

baherus [9]3 years ago

3 0

The standard form of the equation of circle is:

(x – h)^2 + (y – k) ^2 = r^2

Where the center being at the point (h, k) and the radius being r

Substituting the values to the equation:

<span>(-15 - (-7)) ^2 + (y – (-1)) ^2 = 13^2 </span>

64 + (y +1) ^2 = 169

(y +1) ^2 = 105

y + 1 = 10.247

<span>y = 9.247</span>

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In a survey of randomly selected 3,900 family-owned businesses with revenues exceeding $1 million a year, it was found that 1,91

Maurinko [17]

Answer:

a) The 90% confidence interval to estimate the proportion of family-owned businesses without strategic business plans is (0.4768, 0.5032). This means that we are 90% sure that the true proportion of all family-owned businesses without strategic business plans is between these two values.

b) Wider

Step-by-step explanation:

Question a:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , 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 $1 - \frac{\alpha}{2}$ .

In a survey of randomly selected 3,900 family-owned businesses with revenues exceeding $1 million a year, it was found that 1,911 of them had no strategic business plan.

This means that $n = 3900, \pi = \frac{1911}{3900} = 0.49$

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a p-value of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.49 - 1.645\sqrt{\frac{0.49*0.51}{3900}} = 0.4768$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.49 + 1.645\sqrt{\frac{0.49*0.51}{3900}} = 0.5032$

The 90% confidence interval to estimate the proportion of family-owned businesses without strategic business plans is (0.4768, 0.5032). This means that we are 90% sure that the true proportion of all family-owned businesses without strategic business plans is between these two values.

Question b:

The margin of error is:

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

The higher the confidence level, the higher the value of z, thus the higher the margin of error and the interval is wider. Thus, a 99% confidence interval is wider than a 90% confidence interval.

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Dakota earned ?$4.50 in interest in Account A and ?$18.00 in interest in Account B after 18 months. If the simple interest rate

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Answer:

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Step-by-step explanation:

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3 years ago

What is the answer for (14÷49)+((18+7)×9).

balu736 [363]

228.5 I believe. 14/49 is 3.5. 18+7 is 25x9 is 225. 225+3.5 would be 228.5

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Associative property of multiplication

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Convert the complex number z = 4 - 10i from rectangular form to polar form.

mrs_skeptik [129]

ANSWER

$r = 2 \sqrt{29} ( \cos(292 \degree) + \sin(292 \degree))$

EXPLANATION

The polar form of a complex number ,

$z = x + yi$

is given by:

$z = r( \cos( \theta) + i \sin( \theta) )$

where

$r = \sqrt{ {x}^{2} + {y}^{2} }$

The given complex number is:

$z = 4 - 10i$

$r = \sqrt{ {4}^{2} + {( - 10)}^{2} }$

$r = \sqrt{16 + 100}$

$r = \sqrt{116} = 2 \sqrt{29}$

And

$\theta= \tan^{ - 1}(\frac{ y}{x} )$

$\theta= \tan^{ - 1}(\frac{ - 10}{4} )$

$\theta= 292 \degree$

Hence the polar form is :

$r = 2 \sqrt{29} ( \cos(292 \degree) + \sin(292 \degree))$

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3 years ago