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3 years ago

What is the radius of the circle whose equation is x2 + y2 = 8? 2 4 64

Mathematics

2 answers:

Naily [24]3 years ago

8 0

Answer:

The equation of circle of radius r whose centre is the origin (0, 0) ,

It is given by: $x^2+y^2 =r^2$ ......[1]

Given the equation: $x^2+y^2 =8$

To find the radius of the circle;

Compare the given equation with [1] we have;

$r^2 = 8$

Taking square root both sides we get;

$r = \sqrt{8} = 2\sqrt{2}$ units

Therefore, the radius of the circle is, $2\sqrt{2}$ units

umka2103 [35]3 years ago

6 0

It would be
$\sqrt{8}$
Or
$2\sqrt{2}$

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Construct a 99% confidence interval for the population mean, mu. Assume the population has a normal distribution. A group of 1

Zarrin [17]

Answer:

99% confidence interval for the population mean is [19.891 , 24.909].

Step-by-step explanation:

We are given that a group of 19 randomly selected students has a mean age of 22.4 years with a standard deviation of 3.8 years.

Assuming the population has a normal distribution.

Firstly, the pivotal quantity for 99% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean age of selected students = 22.4 years

s = sample standard deviation = 3.8 years

n = sample of students = 19

$\mu$ = population mean

Here for constructing 99% confidence interval we have used t statistics because we don't know about population standard deviation.

So, 99% confidence interval for the population mean, $\mu$ is ;

P(-2.878 < $t_1_8$ < 2.878) = 0.99 {As the critical value of t at 18 degree of

freedom are -2.878 & 2.878 with P = 0.5%}

P(-2.878 < $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ < 2.878) = 0.99

P( $-2.878 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X - \mu}$ < $2.878 \times {\frac{s}{\sqrt{n} } }$ ) = 0.99

P( $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ < $\mu$ < $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ) = 0.99

99% confidence interval for $\mu$ = [ $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ , $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ]

= [ $22.4 -2.878 \times {\frac{3.8}{\sqrt{19} }$ , $22.4 +2.878 \times {\frac{3.8}{\sqrt{19} }$ ]

= [19.891 , 24.909]

Therefore, 99% confidence interval for the population mean is [19.891 , 24.909].

6 0

3 years ago

I want to see if your are smart and tell me what the answer is 50-(14+12+2(5)+2(2)+3

Solnce55 [7]

The answer is 7. If you follow the order of PEMDAS this is an easy question.

7 0

2 years ago

HELP ME ASAP! BRAINLIEST UP FOR GRABS

natita [175]

Answer:

-5 ≤ x≤ 3

Step-by-step explanation:

The domain is the values for x

x starts and -5 and includes -5 since the circle is closed

and goes to 3 and includes 3 since the circle is closed

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8 0

3 years ago

Read 2 more answers

3x^2 + 4x = -8 solve using quadratic formula

Firdavs [7]

Use the quadratic equation to solve this (image of the quadratic equation is below)

Remember that quadratic functions are set up like so:

$ax^{2} +bx +c = 0$

To make the equation 3x² + 4x = -8 into a quadratic function you must bring -8 to the left side of the equation so it equals zero. To do this add 8 to both sides

3x² + 4x + 8= -8 + 8

3x² + 4x + 8 = 0

That means that in this equation...

a = 3

b = 4

c = 8

^^^Plug these numbers into the quadratic equation and solve (Keep in mind that +/- is ± )

$\frac{-4+/-\sqrt{(4)^{2}-4(3)(8)}}{2(3)}$

$\frac{-4+/-\sqrt{16-96}}{6}$

$\frac{-4+/-\sqrt{-80}}{6}$

^^^There is no real solution to this equation. You must have an imaginary solution

$\frac{-4+/-i\sqrt{80}}{6}$

Simplify

$\frac{-2+/-2i \sqrt{5}}{3}$

Hope this helped!

~Just a girl in love with Shawn Mendes

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2 years ago

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lana66690 [7]

Answer:

Step-by-step explanation:

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2 years ago