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3 years ago

!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics

1 answer:

astra-53 [7]3 years ago

4 0

Answer:

maybe the arrows should start from zero, probably

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Aarti is at a garage sale and wants to buy a table that costs $300 she does not have enough cash on her and they don’t have anyt

Firdavs [7]

Answer:

write a check

Step-by-step explanation:

7 0

3 years ago

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Examples for Continuous rv X

11Alexandr11 [23.1K]

Use the definitions of expectation and variance.

Expectation

$E(X) = \displaystyle \int_{-\infty}^\infty x f_X(x) \, dx = \frac14 \int_0^\infty x e^{-x/4} \, dx$

Integrate by parts,

$\displaystyle \int_a^b u \, dv = uv \bigg|_a^b - \int_a^b v \, du$

with

$u = x \implies du = dx \\\\ dv = e^{-x/4} \, dx \implies v = -4 e^{-x/4}$

Then

$E(X) = \displaystyle \frac14 \left(\left(-4x e^{-x/4}\right)\bigg|_0^\infty + 4 \int_0^\infty e^{-x/4} \, dx\right)$

$E(X) = \displaystyle \int_0^\infty e^{-x/4} \, dx = \boxed{4}$

(since the integral of the PDF is 1, and this integral is 4 times that)

Variance

$V(X) = E\bigg((X - E(X))^2\bigg) = E(X^2) - E(X)^2$

Compute the so-called second moment.

$E(X^2) = \displaystyle \int_{-\infty}^\infty x^2 f_X(x)\, dx = \frac14 \int_0^\infty x^2 e^{-x/4} \, dx$

Integrate by parts, with

$u = x^2 \implies du = 2x \, dx \\\\ dv = e^{-x/4} \, dx \implies v = -4 e^{-x/4}$

Then

$E(X^2) = \displaystyle \frac14 \left(\left(-4x^2 e^{-x/4}\right)\bigg|_0^\infty + 8 \int_0^\infty x e^{-x/4} \, dx\right)$

$E(X^2) = 8 E(X) = 32$

and the variance is

$V(X) = 32 - 4^2 = \boxed{16}$

8 0

2 years ago

Oliver is buying a new dishwasher. The dishwasher’s price is $285.10 after tax. He has a few payment options. He can put it on h

ivolga24 [154]

Answer:

omg bussines ughh

8 0

3 years ago

a loaf of bread is cut into slices of equal size. Some of the loaf is used in a recipe and 2/12 of the loaf is used to make a sa

polet [3.4K]

I attached an image with the complete question

Answer:
Fraction of bread used in the recipe is 3/12 which can be further simplified into 1/4

Explanation:
The original loaf of bread is 100% complete (no fraction is taken from it yet). This means that the value of the original loaf is 12/12

Now, assume that the fraction used in the recipe is x
We know that:
2/12 of the loaf was used in making a sandwich
7/12 of the oaf was put in the refrigerator

Therefore:
complete loaf = fraction used in making a sandwich + fraction used in making recipe + fraction put in refrigerator
12/12 = x + 2/12 + 7/12
12/12 = x + 9/12
x = 12/12 - 9/12
x = 3/12

Hope this helps :)

6 0

3 years ago

Need math help please<br>

SashulF [63]

The Y intercept is: (0,7)

4 0

3 years ago

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