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2 years ago

LEVEL 3! HELP PLEASE!

Mathematics

1 answer:

bazaltina [42]2 years ago

6 0

Answer:

abc

Step-by-step explanation:

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Need help best answer gets brainliest

grin007 [14]

288 I’m pretty sure lol

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3 years ago

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How do i find the proportionality of r

Paha777 [63]

Since the graph is a linear function, we're going to use the slope formula solve this:

Note I am replacing m with k
$k= \frac{ y_{2}- y_{1} }{ x_{2}- x_{1} }$

Inserting 2 points from the graph, let's use (1,8) and (2,16).

$\frac{16-8}{2-1}

$

k=8

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3 years ago

Let X ~ N(0, 1) and Y = eX. Y is called a log-normal random variable.

Cloud [144]

If $F_Y(y)$ is the cumulative distribution function for $Y$ , then

$F_Y(y)=P(Y\le y)=P(e^X\le y)=P(X\le\ln y)=F_X(\ln y)$

Then the probability density function for $Y$ is $f_Y(y)={F_Y}'(y)$ :

$f_Y(y)=\dfrac{\mathrm d}{\mathrm dy}F_X(\ln y)=\dfrac1yf_X(\ln y)=\begin{cases}\frac1{y\sqrt{2\pi}}e^{-\frac12(\ln y)^2}&\text{for }y>0\\0&\text{otherwise}\end{cases}$

The $n$ th moment of $Y$ is

$E[Y^n]=\displaystyle\int_{-\infty}^\infty y^nf_Y(y)\,\mathrm dy=\frac1{\sqrt{2\pi}}\int_0^\infty y^{n-1}e^{-\frac12(\ln y)^2}\,\mathrm dy$

Let $u=\ln y$ , so that $\mathrm du=\frac{\mathrm dy}y$ and $y^n=e^{nu}$ :

$E[Y^n]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{nu}e^{-\frac12u^2}\,\mathrm du=\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{nu-\frac12u^2}\,\mathrm du$

Complete the square in the exponent:

$nu-\dfrac12u^2=-\dfrac12(u^2-2nu+n^2-n^2)=\dfrac12n^2-\dfrac12(u-n)^2$

$E[Y^n]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{\frac12(n^2-(u-n)^2)}\,\mathrm du=\frac{e^{\frac12n^2}}{\sqrt{2\pi}}\int_{-\infty}^\infty e^{-\frac12(u-n)^2}\,\mathrm du$

But $\frac1{\sqrt{2\pi}}e^{-\frac12(u-n)^2}$ is exactly the PDF of a normal distribution with mean $n$ and variance 1; in other words, the 0th moment of a random variable $U\sim N(n,1)$ :

$E[U^0]=\displaystyle\frac1{\sqrt{2\pi}}\int_{-\infty}^\infty e^{-\frac12(u-n)^2}\,\mathrm du=1$

so we end up with

$E[Y^n]=e^{\frac12n^2}$

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3 years ago

The blue segment below is a diameter of O. What is the length of the radius of the circle?

svlad2 [7]

Diameter= 2 times the radius

2r=d
2r=10.2
R= 10.2/2
R=5.1

Therefore, the radius is 5.1 units which makes the answer choice C correct.

Hopefully, this helps!

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3 years ago

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To get ready for school supply shopping, a store orders 25,000 folders. The store gets another shipment of 15,250 folders the da

alexandr402 [8]

Answer:

7,850

I’m pretty sure that’s right, I just added 25,000 and 15,250 together then subtracted the answer from 32,400 and got 7,850

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3 years ago