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2 years ago

9

Jayne is driving 440 miles and wants to make the trip in 8 hours. write an equation and solve to determine the average speed jay

ne needs to drive to make the trip in 8 hours. _____

1 answer:

Nuetrik [128]2 years ago

7 0

Distance÷time
440÷8= 55
Therefore he needs to drive at the speed of 55 miles/hour

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How do you use a number line to add integers?

iogann1982 [59]

1. Add a positive integer by moving to the right on the number line.

2. Add a negative integer by moving to the left on the number line.

3. Subtract an integer by adding its opposite.

8 0

3 years ago

If X is a r.v. such that E(X^n)=n! Find the m.g.f. of X,Mx(t). Also find the ch.f. of X,and from this deduce the distribution of

astraxan [27]

$M_X(t)=\mathbb E(e^{Xt})$
$M_X(t)=\mathbb E\left(1+Xt+\dfrac{t^2}{2!}X^2+\dfrac{t^3}{3!}X^3+\cdots\right)$
$M_X(t)=\mathbb E(1)+t\mathbb E(X)+\dfrac{t^2}{2!}\mathbb E(X^2)+\dfrac{t^3}{3!}\mathbb E(X^3)+\cdots$
$M_X(t)=1+t+t^2+t^3+\cdots$
$M_X(t)=\displaystyle\sum_{k\ge0}t^k=\frac1{1-t}$

provided that $|t|$ .

Similarly,

$\varphi_X(t)=\mathbb E(e^{iXt})$
$\varphi_X(t)=1+it+(it)^2+(it)^3+\cdots$
$\varphi_X(t)=(1-t^2+t^4-t^6+\cdots)+it(1-t^2+t^4-t^6+\cdots)$
$\varphi_X(t)=(1+it)(1-t^2+t^4-t^6+\cdots)$
$\varphi_X(t)=\dfrac{1+it}{1+t^2}=\dfrac1{1-it}$

You can find the CDF/PDF using any of the various inversion formulas. One way would be to compute

$F_X(x)=\displaystyle\frac12+\frac1{2\pi}\int_0^\infty\frac{e^{itx}\varphi_X(-t)-e^{-itx}\varphi_X(t)}{it}\,\mathrm dt$

The integral can be rewritten as

$\displaystyle\int_0^\infty\frac{2i\sin(tx)-2it\cos(tx)}{it(1+t^2)}\,\mathrm dt$

so that

$F_X(x)=\displaystyle\frac12+\frac1{2\pi}\int_0^\infty\frac{\sin(tx)-t\cos(tx)}{t(1+t^2)}\,\mathrm dt$

There are lots of ways to compute this integral. For instance, you can take the Laplace transform with respect to $x$ , which gives

$\displaystyle\mathcal L_s\left\{\int_0^\infty\frac{\sin(tx)-t\cos(tx)}{t(1+t^2)}\,\mathrm dt\right\}=\int_0^\infty\frac{1-s}{(1+t^2)(s^2+t^2)}\,\mathrm dt$
$=\displaystyle\frac{\pi(1-s)}{2s(1+s)}$

and taking the inverse transform returns

$F_X(x)=\dfrac12+\dfrac1\pi\left(\dfrac\pi2-\pi e^{-x}\right)=1-e^{-x}$

which describes an exponential distribution with parameter $\lambda=1$ .

6 0

2 years ago

Martin deposits $200 in a savings account that earns 5% annual interest. Four years later, Cary deposits

lesantik [10]

Answer:

200 + (10 y)

Step-by-step explanation:

martin 200 * 5 and divide by 100 =10 per year interest 240 =M

cary 200 + 10=210 =C

200 + (10 y)

4 0

3 years ago

Read 2 more answers

Find the value of n if (81)^5/n = 243

zavuch27 [327]

Answer:

N = 14348907

Step-by-step explanation:

81^5 = 3486784401

3486784401/243 = 14348907

Double Check

3486784401 / 14348907=243

So N = 14348907.

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2 years ago

A combinatio of a translations and a reflection can always be replaced with one transformation

Tema [17]

Answer:

It is correct according to the laws

4 0

8 months ago