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2 years ago

Which number represents the sum of -8 and -i? 0 87 O -87 O --8-7 0 -8 +7

Mathematics

2 answers:

jarptica [38.1K]2 years ago

7 0

The answer is -8+i I hope this help

mafiozo [28]2 years ago

4 0

Answer:

-8+i

Step-by-step explanation:

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Figure ABCD has vertices A(-2,3), B(4,3), C(4,-2), and D(-2,0). What is the area of figure ABCD

zhannawk [14.2K]

Answer:

24 units

Step-by-step explanation:

As we can see in the attached picture. The area will be given by the sum of the area of the rectangle and the area of the triangle in the bottom.

The rectangle has a base of 6 units and a height of 3 units. Therefore:

A1 = bh = 6*3 = 18 units.

The triangle has a base of 6 units and a height of 2 units. Therefore:

A2 = (1/2)bh = (6*2)/ 2 = 6 units

Then, the total area is:

A = A1 + A2 = 6 + 18 = 24 units

6 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

3 years ago

PLS HELP ME 6, 7, and 8 (SHOW WORK!!) + LOTS OF POINTS + THANKS! + BRAINLIEST IF POSSIBLE!

julsineya [31]

6. $1 \frac{1}{2} = \frac{6}{4}$ since $\frac{1}{4} = 4$ feet. Then 6*4=24 So the answer is C

7. 1200 m/8 cm = C. 1 cm = 150 m

8. A. Since 1 in = 3 feet then 6 inches = 18 feet (6*3=18) and 4 inches = 12 feet (4*3=12) so the dimensions of her room are 16'x12'.

B. A=lxw so 16*12= 216 $m^{2}$

Hope that helps

6 0

3 years ago

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What is the center and radius of the circle with the given equation (x-1)^2+(y+1)^2=4?

Mrrafil [7]

<span>The center is x = 1, y = -1.
The radius is 2. </span>

4 0

2 years ago

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zysi [14]

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