All categories

2 years ago

HELP! WHAT IS THIS? WHO WANTS BRAINLEST?? DO STEP BY STEP!

Mathematics

2 answers:

bagirrra123 [75]2 years ago

8 0

I guess

Answer: 4 bracelets, 28 beads, 0 left over, 2 more beads

Step-by-step explanation:

7+7+7+7=28

28-26=2

She needs to more beads to finish and make 4 bracelets

Stolb23 [73]2 years ago

6 0

Answer: 2

Step-by-step explanation:

26 beads divided by 7 is 3 5/7. Then you need to more beads to make another bracelet and not have any beads left over.

You might be interested in

Find the simplified form of the expression. Give your answer in scientific notation. (8x10^4)(9x10^-8)

Orlov [11]

you just have to multiply the bases. 3 x 9 = ? add the exponents of the base 10 10^8(10^7)= 10^(8+7)

6 0

3 years ago

Read 2 more answers

Find the median and mean of the data set below: 47,15, 6, 49, 45, 30

Georgia [21]

Answer:

The median of the data set:

6, 15, 30, 45, 47, 49

The middle numbers are 30 and 45 so

You have to do 30 + 45

= 75

Then do 75 ÷ 2

= 37.5

The mean of the data set:

47, 15, 6, 49, 45, 30 (add them all)

= 192

Then divide 192 by 6 (because there are 6 numbers)

192 ÷ 6

= 32

So the median is 37.5 and the mean is 32.

Step-by-step explanation:

Hope this helps!

From your neighborhood softie :)

5 0

2 years ago

Problem 4: Let F = (2z + 2)k be the flow field. Answer the following to verify the divergence theorem: a) Use definition to find

Viktor [21]

Given that you mention the divergence theorem, and that part (b) is asking you to find the downward flux through the disk $x^2+y^2\le3$ , I think it's same to assume that the hemisphere referred to in part (a) is the upper half of the sphere $x^2+y^2+z^2=3$ .

a. Let $C$ denote the hemispherical cap $z=\sqrt{3-x^2-y^2}$ , parameterized by

$\vec r(u,v)=\sqrt3\cos u\sin v\,\vec\imath+\sqrt3\sin u\sin v\,\vec\jmath+\sqrt3\cos v\,\vec k$

with $0\le u\le2\pi$ and $0\le v\le\frac\pi2$ . Take the normal vector to $C$ to be

$\vec r_v\times\vec r_u=3\cos u\sin^2v\,\vec\imath+3\sin u\sin^2v\,\vec\jmath+3\sin v\cos v\,\vec k$

Then the upward flux of $\vec F=(2z+2)\,\vec k$ through $C$ is

$\displaystyle\iint_C\vec F\cdot\mathrm d\vec S=\int_0^{2\pi}\int_0^{\pi/2}((2\sqrt3\cos v+2)\,\vec k)\cdot(\vec r_v\times\vec r_u)\,\mathrm dv\,\mathrm du$

$\displaystyle=3\int_0^{2\pi}\int_0^{\pi/2}\sin2v(\sqrt3\cos v+1)\,\mathrm dv\,\mathrm du$

$=\boxed{2(3+2\sqrt3)\pi}$

b. Let $D$ be the disk that closes off the hemisphere $C$ , parameterized by

$\vec s(u,v)=u\cos v\,\vec\imath+u\sin v\,\vec\jmath$

with $0\le u\le\sqrt3$ and $0\le v\le2\pi$ . Take the normal to $D$ to be

$\vec s_v\times\vec s_u=-u\,\vec k$

Then the downward flux of $\vec F$ through $D$ is

$\displaystyle\int_0^{2\pi}\int_0^{\sqrt3}(2\,\vec k)\cdot(\vec s_v\times\vec s_u)\,\mathrm du\,\mathrm dv=-2\int_0^{2\pi}\int_0^{\sqrt3}u\,\mathrm du\,\mathrm dv$

$=\boxed{-6\pi}$

c. The net flux is then $\boxed{4\sqrt3\pi}$ .

d. By the divergence theorem, the flux of $\vec F$ across the closed hemisphere $H$ with boundary $C\cup D$ is equal to the integral of $\mathrm{div}\vec F$ over its interior:

$\displaystyle\iint_{C\cup D}\vec F\cdot\mathrm d\vec S=\iiint_H\mathrm{div}\vec F\,\mathrm dV$

We have

$\mathrm{div}\vec F=\dfrac{\partial(2z+2)}{\partial z}=2$

so the volume integral is

$2\displaystyle\iiint_H\mathrm dV$

which is 2 times the volume of the hemisphere $H$ , so that the net flux is $\boxed{4\sqrt3\pi}$ . Just to confirm, we could compute the integral in spherical coordinates:

$\displaystyle2\int_0^{\pi/2}\int_0^{2\pi}\int_0^{\sqrt3}\rho^2\sin\varphi\,\mathrm d\rho\,\mathrm d\theta\,\mathrm d\varphi=4\sqrt3\pi$