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3 years ago

Find the midpoint of (9,2) and (-7,-9)

Mathematics

1 answer:

11Alexandr11 [23.1K]3 years ago

6 0

Answer:

(1,-7/2)

Step-by-step explanation:

The midpoint of (9,2)(-7,-9) is (1,-7/2)

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PLEASE HELP ME ! IMAGE IS BELOW IF YOU GET IT RIGHT I'LL MARK BRAINLIEST

jarptica [38.1K]

Answer:

x = 17

y = 8

QPR = 35º

QRP = 60º

Step-by-step explanation:

2x + 1 = x + 18

Subtract x from both sides

x + 1 = 18

Subtract 1 from both sides

x = 17

QPR = 2x + 1

QPR = 2(17) + 1

QPR = 35º

-------------------------------

8y - 4 = 4y + 28

Subtract 4y from both sides

4y - 4 = 28

Add 4 to both sides

4y = 32

Divide both sides by 4

y = 8

QPR = 8y - 4

QRP = 8(8) - 4

QRP = 60º

7 0

2 years ago

I'm having trouble with #2. I've got it down to the part where it would be the integral of 5cos^3(pheta)/sin(pheta). I'm not sur

Butoxors [25]

$\displaystyle\int\frac{\sqrt{25-x^2}}x\,\mathrm dx$

Setting $x=5\sin\theta$ , you have $\mathrm dx=5\cos\theta\,\mathrm d\theta$ . Then the integral becomes

$\displaystyle\int\frac{\sqrt{25-(5\sin\theta)^2}}{5\sin\theta}5\cos\theta\,\mathrm d\theta$
$\displaystyle\int\sqrt{25-25\sin^2\theta}\dfrac{\cos\theta}{\sin\theta}\,\mathrm d\theta$
$\displaystyle5\int\sqrt{1-\sin^2\theta}\dfrac{\cos\theta}{\sin\theta}\,\mathrm d\theta$
$\displaystyle5\int\sqrt{\cos^2\theta}\dfrac{\cos\theta}{\sin\theta}\,\mathrm d\theta$

Now, $\sqrt{x^2}=|x|$ in general. But since we want our substitution $x=5\sin\theta$ to be invertible, we are tacitly assuming that we're working over a restricted domain. In particular, this means $\theta=\sin^{-1}\dfrac x5$ , which implies that $\left|\dfrac x5\right|\le1$ , or equivalently that $|\theta|\le\dfrac\pi2$ . Over this domain, $\cos\theta\ge0$ , so $\sqrt{\cos^2\theta}=|\cos\theta|=\cos\theta$ .

Long story short, this allows us to go from

$\displaystyle5\int\sqrt{\cos^2\theta}\dfrac{\cos\theta}{\sin\theta}\,\mathrm d\theta$

to

$\displaystyle5\int\cos\theta\dfrac{\cos\theta}{\sin\theta}\,\mathrm d\theta$
$\displaystyle5\int\dfrac{\cos^2\theta}{\sin\theta}\,\mathrm d\theta$

Computing the remaining integral isn't difficult. Expand the numerator with the Pythagorean identity to get

$\dfrac{\cos^2\theta}{\sin\theta}=\dfrac{1-\sin^2\theta}{\sin\theta}=\csc\theta-\sin\theta$

Then integrate term-by-term to get

$\displaystyle5\left(\int\csc\theta\,\mathrm d\theta-\int\sin\theta\,\mathrm d\theta\right)$
$=-5\ln|\csc\theta+\cot\theta|+\cos\theta+C$

Now undo the substitution to get the antiderivative back in terms of $x$ .

$=-5\ln\left|\csc\left(\sin^{-1}\dfrac x5\right)+\cot\left(\sin^{-1}\dfrac x5\right)\right|+\cos\left(\sin^{-1}\dfrac x5\right)+C$

and using basic trigonometric properties (e.g. Pythagorean theorem) this reduces to

$=-5\ln\left|\dfrac{5+\sqrt{25-x^2}}x\right|+\sqrt{25-x^2}+C$

4 0

2 years ago

Read 2 more answers

Paul is 20 years old. He is four times older than his sister.

attashe74 [19]

Answer: Paul will be 30 years old

Step-by-step explanation:Let the age of her sister be x, then from the given data

=> 4x = 20

=> x = 5 years

The age of her sister is 5 years

In the second case, paul is twice as old as his sister

=> Age of paul = 2(x)

=> Age of paul = 10 years

Paul will be 10 years old when he is twice as old as his sister

3 0

1 year ago

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What is the value on the number line for the blue dot

rosijanka [135]

Answer:

I believe 4, but I might be wrong.

Step-by-step explanation:

If you look, it's going down -4 every time. So that means if you're going up, it's going +4 after you skip a space. So, skip, then 0, then skip, and that's 4.

4 0

2 years ago

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Which of the following best describes the volume of a cylinder?

Ahat [919]

<span>A. the area of the circular base multiplied by the height of the cylinder B. the circumference of the circular base multiplied by the height of the cylinder C. the sum of the areas of the two circular bases multiplied by the height of the cylinder D.</span>

4 0

2 years ago