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3 years ago

What is the surface area of the sphere below?

Mathematics

2 answers:

evablogger [386]3 years ago

8 0

Answer:

area of sphere=5πr³=5×π×5²=125πunit²

trasher [3.6K]3 years ago

5 0

The answer is c I’m pretty sure

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Find the value of k if the distance between (2,k) and (6,7) is 4√2 unit

andreyandreev [35.5K]

Answer:

k = 3

Step-by-step explanation:

We have the distance formula: $d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}$ . We can plug in $4\sqrt{2}$ = d, x2 = 6, x1=2, y2 = 7, y1 = k.

Then, we can solve the question using some algebra to find that k = 3.

Edit: Here is a step by step:

$4\sqrt{2} = \sqrt{(6-2)^2 + (7-k)^2}\\$

$(4\sqrt{2})^2 = (6-2)^2 + (7-k)^2$

$32 = (4)^2 + (7-k)^2$

$32 = 16 + (7-k)^2$

$32 - 16 = (7-k)^2$

$16 = (7-k)^2$

$\sqrt{16} = (7-k)$

$4 = 7-k$

$k = 3$

4 0

2 years ago

For the problem below, θ is a central angle in a circle of a radius r. Find the length of arc s cut off by θ.

mixas84 [53]

Answer:

Here, we will use the formula from trigonometry which defines a radian

we know that an angle is a radian when the length of the radius of the circle is equal to the length of the arc formed

hence, if the radius is r and the arc is r, the angle (in radians) will be 1

if the radius is r and the arc is 2r, the angle in radians will be equal to:

length of arc / radius = 2r/r = 2 radians

I believe this will explain what is actually happening in these type of questions

So, the equation:

Θ(in radians) = s / r (where the length of arc is s and the radius is r)

π/4 = s / 12

s = 3π or 9.42 inches

4 0

2 years ago

Solve dis attachment and show all work ( I got it all wrong and I want to know how to solve it )

DedPeter [7]

(a) First find the intersections of $y=e^{2x-x^2}$ and $y=2$ :

$2=e^{2x-x^2}\implies \ln2=2x-x^2\implies x=1\pm\sqrt{1-\ln2}$

So the area of $R$ is given by

$\displaystyle\int_{1-\sqrt{1-\ln2}}^{1+\sqrt{1-\ln2}}\left(e^{2x-x^2}-2\right)\,\mathrm dx$

If you're not familiar with the error function $\mathrm{erf}(x)$ , then you will not be able to find an exact answer. Fortunately, I see this is a question on a calculator based exam, so you can use whatever built-in function you have on your calculator to evaluate the integral. You should get something around 0.5141.

(b) Find the intersections of the line $y=1$ with $y=e^{2x-x^2}$ .

$1=e^{2x-x^2}\implies 0=2x-x^2\implies x=0,x=2$

So the area of $S$ is given by

$\displaystyle\int_0^{1-\sqrt{1-\ln2}}\left(e^{2x-x^2}-1\right)\,\mathrm dx+\int_{1-\sqrt{1-\ln2}}^{1+\sqrt{1-\ln2}}(2-1)\,\mathrm dx+\int_{1+\sqrt{1-\ln2}}^2\left(e^{2x-x^2}-1\right)\,\mathrm dx$
$\displaystyle=2\int_0^{1-\sqrt{1-\ln2}}\left(e^{2x-x^2}-1\right)\,\mathrm dx+\int_{1-\sqrt{1-\ln2}}^{1+\sqrt{1-\ln2}}\mathrm dx$

which is approximately 1.546.

(c) The easiest method for finding the volume of the solid of revolution is via the disk method. Each cross-section of the solid is a circle with radius perpendicular to the x-axis, determined by the vertical distance from the curve $y=e^{2x-x^2}$ and the line $y=1$ , or $e^{2x-x^2}-1$ . The area of any such circle is $\pi$ times the square of its radius. Since the curve intersects the axis of revolution at $x=0$ and $x=2$ , the volume would be given by

$\displaystyle\pi\int_0^2\left(e^{2x-x^2}-1\right)^2\,\mathrm dx$

5 0

3 years ago

How many anagrams are there to the word FRIDAY? In how many of these do the letters 'DAY' appear consecutively? (Disregard wheth

QveST [7]

There are 720 total different combinations, and 24 of those will have the letters DAY consecutively within all those combinations.

<u>Explanation:</u>

FRIDAY is a six letter word.

To form all combinations of letters, we would have six choices of letters to fill the first spot. Whatever letter you choose for the first spot, you then have five choices of letters to fill the second spot. Four choices of letters to fill the third spot. And so on.

So, the total number of different combinations of the six letters would be 6!

6! = 6 X 5 X 4 X 3 X 2 X 1

= 720

DAY could appear consecutively starting in 4 different spots: the 1st, 2nd, 3rd, and 4th spots of all combinations. DAY will appear consecutively 6 times in each of those 4 starting spots.

6 X 4 = 24.

So, there are 720 total different combinations, and 24 of those will have the letters DAY consecutively within all those combinations.

7 0

2 years ago

8 is what percent of 2500

Nataly [62]

8 percent of 2500 is 200.

5 0

2 years ago

Read 2 more answers