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3 years ago

I don’t know how to solve this

Mathematics

2 answers:

LuckyWell [14K]3 years ago

7 0

Answer:

(3x-5)x(3x+5)

Step-by-step explanation:

Calcula el producto

marshall27 [118]3 years ago

7 0

I think the answer is 7?

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Use the given transformation x=4u, y=3v to evaluate the integral. ∬r4x2 da, where r is the region bounded by the ellipse x216 y2

exis [7]

The Jacobian for this transformation is

$J = \begin{bmatrix} x_u & x_v \\ y_u & y_v \end{bmatrix} = \begin{bmatrix} 4 & 0 \\ 0 & 3 \end{bmatrix}$

with determinant $|J| = 12$ , hence the area element becomes

$dA = dx\,dy = 12 \, du\,dv$

Then the integral becomes

$\displaystyle \iint_{R'} 4x^2 \, dA = 768 \iint_R u^2 \, du \, dv$

where $R'$ is the unit circle,

$\dfrac{x^2}{16} + \dfrac{y^2}9 = \dfrac{(4u^2)}{16} + \dfrac{(3v)^2}9 = u^2 + v^2 = 1$

so that

$\displaystyle 768 \iint_R u^2 \, du \, dv = 768 \int_{-1}^1 \int_{-\sqrt{1-v^2}}^{\sqrt{1-v^2}} u^2 \, du \, dv$

Now you could evaluate the integral as-is, but it's really much easier to do if we convert to polar coordinates.

$\begin{cases} u = r\cos(\theta) \\ v = r\sin(\theta) \\ u^2+v^2 = r^2\\ du\,dv = r\,dr\,d\theta\end{cases}$

Then

$\displaystyle 768 \int_{-1}^1 \int_{-\sqrt{1-v^2}}^{\sqrt{1-v^2}} u^2\,du\,dv = 768 \int_0^{2\pi} \int_0^1 (r\cos(\theta))^2 r\,dr\,d\theta \\\\ ~~~~~~~~~~~~ = 768 \left(\int_0^{2\pi} \cos^2(\theta)\,d\theta\right) \left(\int_0^1 r^3\,dr\right) = \boxed{192\pi}$

3 0

2 years ago

Valeria's office recycled a total of 44 kilograms of paper over 4 weeks. How many weeks will it take Valeria's office to recycle

diamong [38]

The answer would be 6 weeks.

First, you do 44 divided by 4 to get 11 kg per week. Now you divide 66 by 11 to get 6 weeks.

8 0

3 years ago

What's the difference between -40ft and 3000ft

Vladimir79 [104]

Answer:

2960 ft.........is the difference between -40ft and 3000ft

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3 years ago

Ivy invested $150 000 in a savings account that offers to pay simple interest of 0.2% per year. How much interest will she recei

kvv77 [185]

Answer:

The answer is the CD was for 3 years.

Step-by-step explanation:

First, write the equation.

I=Prt

Next, substitute the given values.

$198=$1,200×5.5%×t

Next, write the percent as a decimal.

$198=$1,200×0.055×t

Next, simplify.

$198=$66×t

Then, solve for t.

3=t

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2 years ago

What the length of CE?

raketka [301]

Answer:

CE = 3.5

Step-by-step explanation:

25 = x

x = 12.5 perimeter of DCE

4+5+x=12.5

x = 3.5

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3 years ago