I really need help so please be right .Write the radical in simplest radical form and you must show all steps please. √(5/8)

Find the equation of the axis of symmetry of the parabola algebrically y=2x^2+20x+36

solmaris [256]

The answer is x=-15/2
Im not sure how to explain it I’m sorry

7 0

3 years ago

105. Suppose that the probability that an adult in America will watch the Super Bowl is 40%. Each person is considered independe

Ainat [17]

Answer:

a. X is the number of adults in America that need to be surveyed until finding the first one that will watch the Super Bowl.

b. X can take any integer that is greater than or equal to 1. $\rm X\in \mathbb{Z}^{+}$ .

c. $\rm X \sim NB(1, 0.40)$ .

d. $E(\rm X) = 2.5$ .

e. $P(\rm X = 7) = 0.0187$ .

f. $P(\text{X} = 3) +P(\text{X} = 4) = 0.230$ .

Step-by-step explanation:

In this setting, finding an adult in America that will watch the Super Bowl is a success. The question assumes that the chance of success is constant for each trial. The question is interested in the number of trials before the first success. Let X be the number of adults in America that needs to be surveyed until finding the first one who will watch the Super Bowl.

It takes at least one trial to find the first success. However, there's rare opportunity that it might take infinitely many trials. Thus, X may take any integer value that is greater than or equal to one. In other words, X can be any positive integer: $\rm X\in \mathbb{Z}^{+}$ .

There are two discrete distributions that may model X:

The geometric distribution. A geometric random variable measures the number of trials before the first success. This distribution takes only one parameter: the chance of success on each trial.
The negative binomial distribution. A negative binomial random variable measures the number of trials before the r-th success. This distribution takes two parameters: the number of successes $r$ and the chance of success on each trial $p$ .

$\rm NB(1, p)$ (note that $r=1$ ) is equivalent to $\sim Geo(p)$ . However, in this question the distribution of $\rm X$ takes two parameters, which implies that $\rm X$ shall follow the negative binomial distribution rather than the geometric distribution. The probability of success on each trial is $40\% = 0.40$ .

$\rm X\sim NB(1, 0.40)$ .

The expected value of a negative binomial random variable is equal to the number of required successes over the chance of success on each trial. In other words,

$\displaystyle E(\text{X}) = \frac{r}{p} = \frac{1}{0.40} = 2.5$ .

$P(\rm X = 7) = 0.0187$ .

Some calculators do not come with support for the negative binomial distribution. There's a walkaround for that as long as the calculator supports the binomial distribution. The r-th success occurs on the n-th trial translates to (r-1) successes on the first (n-1) trials, plus another success on the n-th trial. Find the chance of (r-1) successes in the first (n-1) trials and multiply that with the chance of success on the n-th trial.

$P(\text{X} = 3)+P(\text{X} = 4) = 0.230$ .

3 0

3 years ago

Solve for x. 2x−5=−x+7

sasho [114]

Answer:

x = 4

Step-by-step explanation

2x−5+x=−x+7+x

3x−5=7

3x−5+5=7+5

3x=12

x=4

4 0

3 years ago

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Find the area of the surface. the part of the sphere x2 + y2 + z2 = 81 that lies above the plane z = 5.

IRISSAK [1]

<span>Here, we only need the upper hemisphere:
z = √(36 - x^2 - y^2).

Note that the cone and sphere intersect at z^2 + z^2 = 36 ==> z = √18
==> The region of integration is x^2 + y^2 + 18 = 36 ==> x^2 + y^2 = 18.

So via Cartesian Coordinates, the surface area equals
∫∫ √[1 + (z_x)^2 + (z_y)^2] dA
= ∫∫ √[1 + (-x/√(36 - x^2 - y^2))^2 + (-y/√(36 - x^2 - y^2))^2] dA
= ∫∫ √[1 + (x^2 + y^2)/(36 - x^2 - y^2)] dA
= ∫∫ √[36/(36 - x^2 - y^2)] dA
= ∫∫ 6 dA/√(36 - x^2 - y^2).

Converting to polar coordinates yields
∫(θ = 0 to 2π) ∫(r = 0 to √18) 6r dr dθ/√(36 - r^2)
= 2π ∫(r = 0 to √18) 6r(36 - r^2)^(-1/2) dr
= 2π * -3 * 2√(36 - r^2) {for r = 0 to √18}
= 12π (6 - 3√2)
= 36π (2 - √2).

I hope this helps! </span>

7 0

4 years ago

0 ft elevation, diver is underwater at depth of 138 ft. In this area, the ocean floor has a depth of 247 ft. A rock formations r

KiRa [710]

We know that the ocean floor has a depth of 247 ft, and we also know that the diver is<span> underwater at depth of 138 ft, so its distance from the ocean floor will be:
</span> $247-138=109$ ft
<span>
Now, the </span>rock formations rises to a peak 171 to above the ocean floor, so to find <span>how many feet below the top of the rock formations is the diver, we are going to subtract the distance to the driver form the ocean floor from the rock formations height:
</span> $171-109=62$ ft
<span>
We can conclude that the diver is 62 feet </span><span>below the top of the rock formations.</span>

3 0

3 years ago

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