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3 years ago

Suppose the diameter of a circle is 6 units .what is it’s circumference?

Mathematics

2 answers:

SVEN [57.7K]3 years ago

7 0

Answer:

about 18.85

Step-by-step explanation:

formula for circumference is 2πr, 2 times pie times radius diameter is 2 times radius or diameter times pi

Murrr4er [49]3 years ago

5 0

Answer:

18.84 units

Step-by-step explanation:

the formula for the circumference is 2× pi × radius.

the radius is half the diameter, so the formula would be 2×pi×6/2

the answer to 2 decimal places is therefore 18.84 units

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~(25 Points)~

murzikaleks [220]

The answer is the third one

3 0

3 years ago

Which variable is most important to the following problem?

Ksenya-84 [330]

Answer:

B.) the number of tents the army orders

Step-by-step explanation:

The word problem does not speak of any prices or tent sizes so it cant be A or C

4 0

2 years ago

Read 2 more answers

Factor completely 3x3 − 6x2 − 24x. 3x(x − 4)(x + 2) 3x(x + 4)(x − 2) 3x(x − 3)(x − 2) 3x(x + 3)(x − 2)

inysia [295]

Answer:

3x(x - 4)(x + 2)

Step-by-step explanation:

Given

3x³ - 6x² - 24x ← factor out common factor of 3x from each term

= 3x(x² - 2x - 8) ← factor the quadratic

Consider the factors of the constant term (- 8) which sum to give the coefficient of the x- term.

The factors are - 4 and + 2, since

- 4 × 2 = - 8 and - 4 + 2 = - 2, thus

x² - 2x - 8 = (x - 4)(x + 2) and

3x³ - 6x² - 24x = 3x(x - 4)(x + 2)

7 0

3 years ago

If you bisect an angle that is 128 degrees, what size are the two new angles?

alina1380 [7]

Answer:

64 is the answer

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5 0

3 years ago

Read 2 more answers

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 <u>c</u>ap $z=\sqrt{3-x^2-y^2}$ , 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:

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

4 0

3 years ago