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2 years ago

I WILL MARK BRAINLIEST FOR CORRECT ANSWER! :)

Mathematics

1 answer:

natita [175]2 years ago

8 0

Answer: 31.2

Step-by-step explanation:

have a great dayy

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Ms. Halloran and Ms. Scott were attending the concert

nlexa [21]

Answer: B

I hope this helped you

6 0

2 years ago

Read 2 more answers

Plz I need the awnser to this

Scilla [17]

Answer:A

Step-by-step explanation: because it’s an even number

8 0

3 years ago

Let X1, X2, ... , Xn be a random sample from N(μ, σ2), where the mean θ = μ is such that −[infinity] < θ < [infinity] and

Sliva [168]

Answer:

$l'(\theta) = \frac{1}{\sigma^2} \sum_{i=1}^n (X_i -\theta)$

And then the maximum occurs when $l'(\theta) = 0$ , and that is only satisfied if and only if:

$\hat \theta = \bar X$

Step-by-step explanation:

For this case we have a random sample $X_1 ,X_2,...,X_n$ where $X_i \sim N(\mu=\theta, \sigma)$ where $\sigma$ is fixed. And we want to show that the maximum likehood estimator for $\theta = \bar X$ .

The first step is obtain the probability distribution function for the random variable X. For this case each $X_i , i=1,...n$ have the following density function:

$f(x_i | \theta,\sigma^2) = \frac{1}{\sqrt{2\pi}\sigma} exp^{-\frac{(x-\theta)^2}{2\sigma^2}} , -\infty \leq x \leq \infty$

The likehood function is given by:

$L(\theta) = \prod_{i=1}^n f(x_i)$

Assuming independence between the random sample, and replacing the density function we have this:

$L(\theta) = (\frac{1}{\sqrt{2\pi \sigma^2}})^n exp (-\frac{1}{2\sigma^2} \sum_{i=1}^n (X_i-\theta)^2)$

Taking the natural log on btoh sides we got:

$l(\theta) = -\frac{n}{2} ln(\sqrt{2\pi\sigma^2}) - \frac{1}{2\sigma^2} \sum_{i=1}^n (X_i -\theta)^2$

Now if we take the derivate respect $\theta$ we will see this:

$l'(\theta) = \frac{1}{\sigma^2} \sum_{i=1}^n (X_i -\theta)$

And then the maximum occurs when $l'(\theta) = 0$ , and that is only satisfied if and only if:

$\hat \theta = \bar X$

6 0

3 years ago

If cosθ=40/41,find sinθ,cotθ,secθ

fgiga [73]

Hello.

Angle Theta is equal to: x² + y² = r² OR $r = \sqrt{ x^{2} + y^{2} }$

40² + y² = 41²
1600 + y² = 1681
-1600 -1600
y² = 81
y = 9

x = 40, y = 9, r = 41

<span>cos θ= </span> $\frac{x}{r}$ = $\frac{40}{41}$

sin θ = $\frac{y}{r} = \frac{9}{41}$
cot θ = $\frac{x}{y} = \frac{40}{9}$
sec θ = $\frac{r}{x} = \frac{41}{40}$

Hopefully it makes sense! :)

6 0

3 years ago

A plane flying from City A to City B travels x miles per hour for a total of 4.5 hours. The plane takes the same route on the re

Oksana_A [137]

Answer:

1800 miles

Step-by-step explanation:

Distance = rate X time. D=R x T

d=x(4.5)

d=4.5x. (First trip)

D=(x+25)(4)

D= 4x + 100. (Return trip)

Total distance

4.5x = 4x +100

X = 200

4.5(200) = 4(200) + 100

1800

4 0

2 years ago