Simplify the expression,<br><br> 4/9z - 3/9z + 4 - 5/9z

Find and sketch the domain of the function. f(x,y)=√(4-x^2-y^2) +√(1-x^2)<br>

elena55 [62]

Answer:

Hello

Step-by-step explanation:

The domain is limited with 2 lines parallel: -1 ≤ x ≤ 1

and the disk ? (inside of a circle) of center (0,0) and radius 2

$dom\ f(x,y)=\{(x,y) \in \mathbb{R} ^2 | \ -1\leq x \leq -1\ and \ ( -\sqrt{4-x^2} \leq \ y \leq \sqrt{4-x^2}\ ) \ \}\\$

3 0

3 years ago

Suppose a baker claims that the average bread height is more than 15cm. Several of this customers do not believe him. To persuad

laila [671]

Answer:

$17-2.262\frac{1.9}{\sqrt{10}}=15.641$

$17+2.262\frac{1.9}{\sqrt{10}}=18.359$

So on this case the 95% confidence interval would be given by (15.641;18.359)

And since the lower limit for the confidence interval is higher than 15 we can conclude that at 5% of significance the true mean is higher than 15 cm

Step-by-step explanation:

Previous concepts

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".

$\bar X=17$ represent the sample mean

$\mu$ population mean (variable of interest)

s=1.9 represent the sample standard deviation

n=10 represent the sample size

Confidence interval

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

$df=n-1=10-1=9$

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(0.025,9)".And we see that $t_{\alpha/2}=2.262$

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

$17-2.262\frac{1.9}{\sqrt{10}}=15.641$

$17+2.262\frac{1.9}{\sqrt{10}}=18.359$

So on this case the 95% confidence interval would be given by (15.641;18.359)

And since the lower limit for the confidence interval is higher than 15 we can conclude that at 5% of significance the true mean is higher than 15 cm

4 0

3 years ago

Your cousin is 8 years older than your brother. Three years ago, your cousin was twice as old as your brother. How old is your c

ValentinkaMS [17]

Answer:

19 and 11

Step-by-step explanation:

8 0

3 years ago

Will mark most brainlest if correct

lutik1710 [3]

Answer: each guest gets 4.19 cm²

Step-by-step explanation:

The cake is a circle. The area which he cuts for himself is a sector with a central angle of 120 degrees. The formula for determining the area of a sector is expressed as

Area of sector = θ/360 × πr²

Where

θ represents the central angle

π is a constant whose value is 3.14

r represents the radius of the circle.

From the diagram,

r = 4cm

Therefore, area of the cake that he cut for himself is

120/360 × 3.14 × 4²

= 16.75 cm²

The total area of the cake is

3.14 × 4² = 50.24 cm²

Therefore, the rest of the cake is

50.24 - 16.75 = 33.49 cm²

The amount that each guest gets would be

33.49/8 = 4.19 cm²

8 0

3 years ago

What is a rational number?

yuradex [85]

Answer:a rational number is any number that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q.

8 0

3 years ago

Simplify the expression, 4/9z - 3/9z + 4 - 5/9z - 9 =