The function f(x) varies directly with x and f(x)=250 when x=50

From an airplane flying over the ocean, the angle of depression to a submarine lying under the surface if 24 degrees 10 minutes.

forsale [732]

I think is 10 m/ s per sec

4 0

2 years ago

Tara wants to put a white fence aroung the yard including the garden. Write an

Cerrena [4.2K]

The perimeter of a rectangle is 2L + 2W, where L and W are the length and width, respectively. The dimensions of the garden are given, 6 x 12 ft.

The amount of fencing needed is 2(6) + 2(12) = 12 + 24 = 36 ft of fencing

6 0

2 years ago

If the volume of the figure below is 4,069.44ft3 find the missing dimension

olga_2 [115]

Answer:

x = 9 ft

Step-by-step explanation:

The volume of a cylinder is given by

V = pi r^2 h

We know the radius is x

4069.44 = pi x^2 16

Divide each side by 16 pi

4069.44 / 16 pi = x^2

Using 3.14 for pi

81 = x^2

Take the square root of each side

sqrt(81) = sqrt(x^2)

x = 9

3 0

3 years ago

I have <img src="https://tex.z-dn.net/?f=%20%5Cfrac%7Bdx%7D%7Bdt%7D%20%3D%20%20%5Cfrac%7B5%7D%7Bx%7D%20" id="TexFormula1" title=

mojhsa [17]

$\bf \cfrac{dx}{dt}=\cfrac{5}{t}\quad ,\quad x(0)=7\to 
\begin{cases}
f(t)=0\\
t=7
\end{cases}\\\\
-----------------------------\\\\
\displaystyle \int \cfrac{5}{t}\cdot dt\implies 5\int \cfrac{1}{t}\cdot dt\implies 5ln|t|+C= f(t)
\\\\\\
\textit{now, we know when f(t)=0, t=7}\implies 5ln|7|+C=0
\\\\\\
C=-5ln(7)
\\\\\\
thus\implies \boxed{5ln|t|-5ln(7)=f(t)=x}$

notice |7| 7 is positive, so we can simply remove the bars and use 7 by itself

6 0

3 years ago

A sanitation department is interested in estimating the mean amount of garbage per bin for all bins in the city. In a random sam

soldi70 [24.7K]

Answer:

a) $52.8-2.02\frac{3.9}{\sqrt{40}}=51.554$

b) $52.8+2.02\frac{3.9}{\sqrt{40}}=54.046$

c) $52.8-2.71\frac{3.9}{\sqrt{40}}=51.129$

d) $52.8+2.71\frac{3.9}{\sqrt{40}}=54.471$

e) Yes, depends of the confidence level.

At 95 % of confidence the value 54.1985 pounds is not included on the interval. At 5% of significance the statement is FALSE.

At 99 % of confidence the value 54.1985 pounds is included on the interval. So at 1% of significance the statement is TRUE.

Step-by-step explanation:

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X =52.8$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=3.9 represent the sample standard deviation

n=40 represent the sample size

a) What is the lower limit of the 95% interval? Give your answer to three decimal places

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=40-1=39$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,39)".And we see that $t_{\alpha/2}=2.02$

Now we have everything in order to replace into formula (1):

$52.8-2.02\frac{3.9}{\sqrt{40}}=51.554$

b) What is the upper limit of the 95% interval? Give your answer to three decimal places

$52.8+2.02\frac{3.9}{\sqrt{40}}=54.046$

So on this case the 95% confidence interval would be given by (51.554;54.046)

c) What is the lower limit of the 99% interval? Give your answer to three decimal places

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,39)".And we see that $t_{\alpha/2}=2.71$

Now we have everything in order to replace into formula (1):

$52.8-2.71\frac{3.9}{\sqrt{40}}=51.129$

d) What is the upper limit of the 99% interval? Give your answer to three decimal places

$52.8+2.71\frac{3.9}{\sqrt{40}}=54.471$

So on this case the 99% confidence interval would be given by (51.129;54.471)

e) Consider the claim that the mean amount of garbage per bin is 54.1985 pounds. Is the following statement true or false? The decision about the claim would depend on whether we use a 95% or 99% confidence interval: True/False

Yes, depends of the confidence level.

At 95 % of confidence the value 54.1985 pounds is not included on the interval. At 5% of significance the statement is FALSE.

At 99 % of confidence the value 54.1985 pounds is included on the interval. So at 1% of significance the statement is TRUE.

3 0

3 years ago