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3 years ago

PLEASE HELP MEEE I DONT GET THISSSSS

Mathematics

1 answer:

KiRa [710]3 years ago

4 0

Answer:

Root is a fancy word for a zero.

Using the quadratic formula you will get

x = 1.2, -.25

B is the correct answer. (-1/4)

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Naya [18.7K]

D) 5

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3 years ago

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Which statements are true about the rules of multiplication for signed numbers? Check all that apply.

Mekhanik [1.2K]

Answer:

i think that 1, 3 and 4 are correct !!

Step-by-step explanation:

youre welcome, have a nice day!

NOTE: next time please provide the list of choices so it can be easier to help you

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4 years ago

The product of two mixed numbers x and y is 10. If x= _ 2/3 and y=_ 3/4 , find x and y?

Akimi4 [234]

Answer:

x = 2 2/3
y = 3 3/4

Step-by-step explanation:

There may be other ways to do this. Here's the approach I took. Let the integer part of x be represented by "a", and the integer part of y be represented by "b". Now, we have ...

(a +2/3)(b +3/4) = 10

Multiplying by 12, this becomes ...

(3a +2)(4b +3) = 120

There are only 16 divisors of 120, so they can be easily enough checked one at a time.

120 = 1·120 = 2·60 = 3·40 = 4·30 = 5·24 = 6·20 = 8·15 = 10·12

Of these divisors, the ones that are of the form 3a+2 are ...

2, 5, 8, 20 . . . . a=0, 1, 2, 6

The ones that are of the form 4b+3 are ...

3, 15 . . . . b = 0, 3

The factor pair that consists of a number on the first list and a number on the second list is ...

120 = 8·15

corresponding to a=2 and b=3. So, the mixed numbers you want are ...

x = 2 2/3

y = 3 3/4

_____

Check

(2 2/3)·(3 3/4) =2·3 +2·3/4 +2/3·3 +2/3·3/4 = 6 +6/4 +2 +2/4 = 8+8/4 = 10

6 0

3 years ago

For each of the following numbers, write 4 decimals that would round to this whole number when rounde to the nearest whole numbe

Natalka [10]

Round to the nearest whole number:

a) 14 ⇒ 13.5 ; 13.9 ; 14.1 ; 14.4
b) 28 ⇒ 27.5 ; 27.9 ; 28.1 ; 28.4
c) 32 ⇒ 31.5 ; 31.9 ; 32.1 ; 32.4
d) 50 ⇒ 49.5 ; 49.9 ; 50.1 ; 50.4
e) 67 ⇒ 66.5 ; 66.9 ; 67.1 ; 67.4
f) 71 ⇒ 70.5; 70.9 ; 71.1 ; 71.4
g) 88 ⇒ 87.5; 87.9 ; 88.1 ; 88.4
h) 95 ⇒ 94.5; 94.9 ; 95.1 ; 95.4

If the following number is within the range of 1 to 4 then round down.
If the following number is within the range of 5 to 9 then round up.

8 0

3 years ago

What's the flux of the vector field F(x,y,z) = (e^-y) i - (y) j + (x sinz) k across σ with outward orientation where σ is the po

emmasim [6.3K]

$\displaystyle\iint_\sigma\mathbf F\cdot\mathrm dS$
$\displaystyle\iint_\sigma\mathbf F\cdot\mathbf n\,\mathrm dS$
$\displaystyle\iint_\sigma\mathbf F\cdot\left(\frac{\mathbf r_u\times\mathbf r_v}{\|\mathbf r_u\times\mathbf r_v\|}\right)\|\mathbf r_u\times\mathbf r_v\|\,\mathrm dA$
$\displaystyle\iint_\sigma\mathbf F\cdot(\mathbf r_u\times\mathbf r_v)\,\mathrm dA$

Since you want to find flux in the outward direction, you need to make sure that the normal vector points that way. You have

$\mathbf r_u=\dfrac\partial{\partial u}[2\cos v\,\mathbf i+\sin v\,\mathbf j+u\,\mathbf k]=\mathbf k$
$\mathbf r_v=\dfrac\partial{\partial v}[2\cos v\,\mathbf i+\sin v\,\mathbf j+u\,\mathbf k]=-2\sin v\,\mathbf i+\cos v\,\mathbf j$

The cross product is

$\mathbf r_u\times\mathbf r_v=\begin{vmatrix}\mathbf i&\mathbf j&\mathbf k\\0&0&1\\-2\sin v&\cos v&0\end{vmatrix}=-\cos v\,\mathbf i-2\sin v\,\mathbf j$

So, the flux is given by

$\displaystyle\iint_\sigma(e^{-\sin v}\,\mathbf i-\sin v\,\mathbf j+2\cos v\sin u\,\mathbf k)\cdot(\cos v\,\mathbf i+2\sin v\,\mathbf j)\,\mathrm dA$
$\displaystyle\int_0^5\int_0^{2\pi}(-e^{-\sin v}\cos v+2\sin^2v)\,\mathrm dv\,\mathrm du$
$\displaystyle-5\int_0^{2\pi}e^{-\sin v}\cos v\,\mathrm dv+10\int_0^{2\pi}\sin^2v\,\mathrm dv$
$\displaystyle5\int_0^0e^t\,\mathrm dt+5\int_0^{2\pi}(1-\cos2v)\,\mathrm dv$

where $t=-\sin v$ in the first integral, and the half-angle identity is used in the second. The first integral vanishes, leaving you with

$\displaystyle5\int_0^{2\pi}(1-\cos2v)\,\mathrm dv=5\left(v-\dfrac12\sin2v\right)\bigg|_{v=0}^{v=2\pi}=10\pi$

5 0

3 years ago