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2 years ago

PLS HELP ASAP THANKS ILL GIVE BRAINLKEST PLS THANKS PLS ASAP PLS PLS

Mathematics

1 answer:

Murrr4er [49]2 years ago

3 0

Answer: It is D and I

Step-by-step explanation:

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3 ice cream cones cost $8.25. At this rate, how much would 5 ice cream cones cost?

Dmitriy789 [7]

Five ice cream cones would cost 13.75 at the rate that each cone costs 2.75

5 0

2 years ago

1/4,5/8,1/2<br><br> I need the fractions in least to greatest

djyliett [7]

1/4 is the least, 1/2 is next, then 5/8 as the greatest.

4 0

3 years ago

Read 2 more answers

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

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

3 0

2 years ago

A rectangle has length 72 cm and width 56 cm. The other rectangle has the same area as this one, but its width is 21 cm. What is

Ira Lisetskai [31]

The length of the rectangle is = 72 cm

The width of the rectangle is = 56 cm

Area of the rectangle is = $length*width$

= $72\times56=4032$ cm²

As given, the other rectangle has the same area as this one, but its width is 21 cm.

Let the length here be = x

$4032=x*21$

$x=\frac{4032}{21}=192$

Hence, length is 192 cm.

We can see that as width decreases, the length increases if area is constant and when length decreases then width increases if area is constant.

So, in the new rectangle,constant of variation=k is given by,

$\frac{192}{72}=\frac{8}{3}$ or $\frac{56}{21}=\frac{8}{3}$

Hence, the constant of variation is $\frac{8}{3}$

7 0

2 years ago

The domain of: x+3 under square root

Gennadij [26K]

Answer:

All real numbers except where x<-3

Step-by-step explanation:

Values of x that make negatives under even radicals are not part of the domain. Any value of x that is less than -3 would make a negative under the square root, so those are not included in the domain.

3 0

2 years ago