1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
antiseptic1488 [7]
3 years ago
13

What is the circumference of the semicircle

Mathematics
2 answers:
deff fn [24]3 years ago
5 0

Answer:

this answer is attached to the picture

Olin [163]3 years ago
3 0

Answer:

12.56m

Step-by-step explanation:

\frac{180}{360}  \times 2\pi \: r \\  \frac{1}{2}  \times 2 \times \pi \times 4 \\  = 12.56m

You might be interested in
The quotient of a number and three is equal to negative eight
GuDViN [60]
There are multiple answers to this
7 0
3 years ago
A triangle with side lengths a, b, and c is shown below.
nataly862011 [7]

Answer:

a+c=b

hope it helps you

bye

7 0
2 years ago
Read 2 more answers
Whoevr answers this question correctly gets brainly<br><br>and show your work please
blsea [12.9K]

Answer:

1/4

Step-by-step explanation:

The chance of it landing heads up once would be 1/2

The chance of it landing heads up twice would be 1/4

The chance of it landing heads up three times would be 1/8

The chance of it landing heads up four times would be 1/16

See the pattern?

Pattern:  <em><u>Divide the denominator by 2.</u></em>

<h2><em>Please give brainliest!!! :) </em></h2>

3 0
3 years ago
The lifetime X (in hundreds of hours) of a certain type of vacuum tube has a Weibull distribution with parameters α = 2 and β =
stich3 [128]

I'm assuming \alpha is the shape parameter and \beta is the scale parameter. Then the PDF is

f_X(x)=\begin{cases}\dfrac29xe^{-x^2/9}&\text{for }x\ge0\\\\0&\text{otherwise}\end{cases}

a. The expectation is

E[X]=\displaystyle\int_{-\infty}^\infty xf_X(x)\,\mathrm dx=\frac29\int_0^\infty x^2e^{-x^2/9}\,\mathrm dx

To compute this integral, recall the definition of the Gamma function,

\Gamma(x)=\displaystyle\int_0^\infty t^{x-1}e^{-t}\,\mathrm dt

For this particular integral, first integrate by parts, taking

u=x\implies\mathrm du=\mathrm dx

\mathrm dv=xe^{-x^2/9}\,\mathrm dx\implies v=-\dfrac92e^{-x^2/9}

E[X]=\displaystyle-xe^{-x^2/9}\bigg|_0^\infty+\int_0^\infty e^{-x^2/9}\,\mathrm x

E[X]=\displaystyle\int_0^\infty e^{-x^2/9}\,\mathrm dx

Substitute x=3y^{1/2}, so that \mathrm dx=\dfrac32y^{-1/2}\,\mathrm dy:

E[X]=\displaystyle\frac32\int_0^\infty y^{-1/2}e^{-y}\,\mathrm dy

\boxed{E[X]=\dfrac32\Gamma\left(\dfrac12\right)=\dfrac{3\sqrt\pi}2\approx2.659}

The variance is

\mathrm{Var}[X]=E[(X-E[X])^2]=E[X^2-2XE[X]+E[X]^2]=E[X^2]-E[X]^2

The second moment is

E[X^2]=\displaystyle\int_{-\infty}^\infty x^2f_X(x)\,\mathrm dx=\frac29\int_0^\infty x^3e^{-x^2/9}\,\mathrm dx

Integrate by parts, taking

u=x^2\implies\mathrm du=2x\,\mathrm dx

\mathrm dv=xe^{-x^2/9}\,\mathrm dx\implies v=-\dfrac92e^{-x^2/9}

E[X^2]=\displaystyle-x^2e^{-x^2/9}\bigg|_0^\infty+2\int_0^\infty xe^{-x^2/9}\,\mathrm dx

E[X^2]=\displaystyle2\int_0^\infty xe^{-x^2/9}\,\mathrm dx

Substitute x=3y^{1/2} again to get

E[X^2]=\displaystyle9\int_0^\infty e^{-y}\,\mathrm dy=9

Then the variance is

\mathrm{Var}[X]=9-E[X]^2

\boxed{\mathrm{Var}[X]=9-\dfrac94\pi\approx1.931}

b. The probability that X\le3 is

P(X\le 3)=\displaystyle\int_{-\infty}^3f_X(x)\,\mathrm dx=\frac29\int_0^3xe^{-x^2/9}\,\mathrm dx

which can be handled with the same substitution used in part (a). We get

\boxed{P(X\le 3)=\dfrac{e-1}e\approx0.632}

c. Same procedure as in (b). We have

P(1\le X\le3)=P(X\le3)-P(X\le1)

and

P(X\le1)=\displaystyle\int_{-\infty}^1f_X(x)\,\mathrm dx=\frac29\int_0^1xe^{-x^2/9}\,\mathrm dx=\frac{e^{1/9}-1}{e^{1/9}}

Then

\boxed{P(1\le X\le3)=\dfrac{e^{8/9}-1}e\approx0.527}

7 0
3 years ago
the length of a table is 6 feet. on a scale drawing, the length is 2 inches. write three possible scales for the drawing
butalik [34]
2 inches : 6 feet is the same as 1 inch : 3 feet
It could also be written:
1 inch : 36 inches
1 foot : 36 feet
8 0
3 years ago
Other questions:
  • Need help on #18 please
    13·1 answer
  • the area of a rectangle is 56 centimeters. The length is 2 centimeters more than x and the width is 5 Centimeters less than twic
    13·1 answer
  • Base ten numeral<br><br> What is Two and four hundred fifty eight thousandths?
    13·2 answers
  • The Serenity and the Mystic are sailboats. The Serenity and the Mystic start at the same point and travel away from each other i
    13·1 answer
  • Hi can you help me in mate plis<br>simplify the following algebraic expressions​
    14·1 answer
  • If a polynomial has two factors: It will either have two zeros or the same zero twice.
    6·1 answer
  • An isosceles triangle has base length 18 cm and height 4cm what is the approximate length of the two other sides
    15·1 answer
  • How to find the area using the net of a pyramid
    6·1 answer
  • HELP QUICK! I GIVE BRAINLIEST!! What are the correct values for the missing boxes in the ratio table in number 3 above
    14·1 answer
  • HELP ASAP PLEASE!!!!!!
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!