2 years ago

SUPER EASY, WILL GIVE BRAINLIEST What’s the domain of quadratic functions?

Mathematics

2 answers:

Snowcat [4.5K]2 years ago

6 0

Answer:

1st option!!

Good Luck!!!

Zigmanuir [339]2 years ago

3 0

Answer:

[0,∞)

I hope this is good enough:

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PLEASE HELP PLEASE PLEASE PLEASE

sleet_krkn [62]

Answer:

oh no that's tough bro

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2 years ago

A diver begins at sea level and descends vertically at a rate of 2 1/2 ft. per second. How long does the diver take to reach -15

galina1969 [7]

2 1/2 feet can be written as 2.5 feet.

Divide the total distance by the distance per second:

15.6 feet / 2.5 feet per second = 6.24 seconds.

7 0

3 years ago

A 9-pack of golf balls costs $8.74. What is the unit price, rounded to the nearest cent?

MrRa [10]

Answer:

0.97 per ball

Step-by-step explanation:

Take the total cost and divide by the number of items

8.74 /9

0.97111

Rounding to the nearest cent

0.97

5 0

3 years ago

someone pls help!! NO LINKS AND ONLY ANSWER IF U KNOW!! i’ll report u if u do either. pls explain well too

erica [24]

Answer:

can u please send the question again with clear picture of diagram?

7 0

3 years ago

G with the definition of covariance, prove cov[(ay − b),(cy − d)] = accov(x, y ), where x, y are random variables and a, b, c, d

____ [38]

By definition of covariance,

$\mathrm{Cov}(X,Y)=\mathbb E[(X-\mathbb E[X])(Y-\mathbb E[Y])]$

$\mathrm{Cov}(X,Y)=\mathbb E[XY-\mathbb E[X]Y-X\mathbb E[Y]+\mathbb E[X]\mathbb E[Y]]=\mathbb E[XY]-\mathbb E[X]\mathbb E[Y]$

We have

$\mathbb E[(aX-b)(cY-d)]=\mathbb E[acXY-adX-bcY+bd]$

$=ac\mathbb E[XY]-ad\mathbb E[X]-bc\mathbb E[Y]+bd$

$\mathbb E[aX-b]=a\mathbb E[X]-b$

$\mathbb E[cY-d]=c\mathbb E[Y]-d$

$\mathbb E[aX-b]\mathbb E[cY-d]=ac\mathbb E[X]\mathbb E[Y]-ad\mathbb E[X]-bc\mathbb E[Y]+bd$

Putting everything together, we find the covariance reduces to

$\mathrm{Cov}(aX-b,cY-d)=ac(\mathbb E[XY]-\mathbb E[X]\mathbb E[Y])=ac\mathrm{Cov}(X,Y)$

as desired.

5 0

3 years ago