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bogdanovich [222]
3 years ago
15

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

Mathematics
2 answers:
gavmur [86]3 years ago
5 0
If that is x^2+y^2=8
then the radius is 2\sqrt{2}
ikadub [295]3 years ago
5 0

Answer:

The radius of the circle whose equation is x^{2}+y^{2}=8 is 2\sqrt{2}

Step-by-step explanation:

The equation of a circle centered at the origin (0,0) and radius R is :

x^{2}+y^{2}=R^{2} (I)

Where ''R'' is a real number.

For the equation given, we know that

R^{2}=8 ⇒

R=\sqrt{8}

R=\sqrt{(2).(4)}

R=2\sqrt{2}

We found out that the radius of the circle is R=2\sqrt{2}

For another circle, for example centered at the point (a,b) and radius R the equation is :

(x-a)^{2}+(y-b)^{2}=R^{2}  (II)

Notice that if we replace the point (a,b) by (0,0) ⇒

(x-0)^{2}+(y-0)^{2}=R^{2} ⇒

x^{2}+y^{2}=R^{2}

We obtain the equation (I).

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Michael is buying a pair of jeans that regularly cost $40. They are on sale for 20% off. If the tax rate is 8%, what is the sale
Anna35 [415]

Answer      

Find out the  what is the sale price of the jeans including tax .

To prove

Let us assume that the sale price of the jeans including tax be x .

As given

Michael is buying a pair of jeans that regularly cost $40.

They are on sale for 20% off.

If the tax rate is 8% .

20% is written in the decimal form

= \frac{20}{100}

= 0.20

8% is written in the decimal form

= \frac{8}{100}

= 0.08

Than the equation becomes

x = 40 - 40 × 0.20 + 40 × 0.08

x = 40 - 8 + 3.2

x = 43.2 - 8

x = $35.2

Therefore the sale price of the jeans including tax be $ 35.2 .



4 0
3 years ago
Soap films and bubbles are colorful because the interference conditions depend on the angle of illumination (which we aren't cov
mylen [45]

Answer:

56.39 nm

Step-by-step explanation:

In order to have constructive interference total optical path difference should be an integral number of wavelengths (crest and crest should be interfered). Therefore the constructive interference condition for soap film can be written as,

2t=(m+\frac{1}{2} ).\frac{\lambda}{n}

where λ is the wavelength of light and n is the refractive index of soap film, t is the thickness of the film, and m=0,1,2 ...

Please note that here we include an additional 1/2λ phase shift due to reflection from air-soap interface, because refractive index of latter is higher.

In order to have its longest constructive reflection at the red end (700 nm)

t_1=(m+\frac{1}{2} ).\frac{\lambda}{2.n}\\ \\ t_1=\frac{1}{2} .\frac{700}{(2)*(1.33)}\\ \\ t_1=131.58\ nm

Here we take m=0.

Similarly for the constructive reflection at the blue end (400 nm)

t_2=(m+\frac{1}{2} ).\frac{\lambda}{2.n}\\ \\ t_2=\frac{1}{2} .\frac{400}{(2)*(1.33)}\\ \\ t_2=75.19\ nm

Hence the thickness difference should be

t_1-t_2=131.58-75.19=56.39 \ nm

7 0
3 years ago
Suppose the scores of students on an exam are normally distributed with a mean of 244 and a standard deviation of 79. According
Ahat [919]
244 - 165 = 79 . . . . one standard deviation
323 - 244 = 79 . . . . one standard deviation

The range of scores is ±1 standard deviation from the mean. The empirical rule says 
   68% of scores lie in that range.
3 0
3 years ago
Jenny has nine marbles, but her best friend Susie gives her ten more! However, the neighborhood bully, Danny, steals four marble
Dimas [21]

Answer:

Jenny has 50 marbles

Step-by-step explanation:

I find it easiest to right down the numbers as I read the question,

(9+10-4) x3 +7-2

8 0
3 years ago
Find the value of X. Then find the measure of each labeled angle.
wariber [46]
Both angles WILL have the same measure.

So,

3x-10= x+40 (you have to set the equations equal to one another)


Now, add 10 to both sides.

3x=x+50

Subtract x on both sides.

2x=50

Divide both sides by 2.

x=25

Now, plug in x.

(25 +40)= 65

(3(25)-10)= 65

x equals 25 and both angles are equal to 65. Or "B".

I hope this helps!
~cupcake
5 0
3 years ago
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