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3 years ago

I Plz help I’m getting timed

Mathematics

1 answer:

topjm [15]3 years ago

6 0

Answer:

2 2/3 + 2 1/3 = 5

Step-by-step explanation:

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Evaluate the integral by making an appropriate change of variables.

VARVARA [1.3K]

By inspecting the integrand, the "obvious" choice for substitution would be

u = y + x

v = y - x

Solving for x and y, we would have

x = (u - v)/2

y = (u + v)/2

in which case the Jacobian and its determinant are

$J=\begin{bmatrix}x_u&x_v\\y_u&y_v\end{bmatrix}=\dfrac12\begin{bmatrix}1&-1\\1&1\end{bmatrix}\implies|\det J|=\left|\dfrac12\right|=\dfrac12$

The trapezoid R has two of its edges on the lines x + y = 8 and x + y = 9, so right away, we have 8 ≤ u ≤ 9.

Then for v, we observe that when x = 0 (the lowest edge of R), v = y ; similarly, when y = 0 (the leftmost edge of R), v = -x. So

-x ≤ v ≤ y

-(u - v)/2 ≤ v ≤ (u + v)/2

-u + v ≤ 2v ≤ u + v

-u ≤ v ≤ u

So, the integral becomes

$\displaystyle\iint_R5\cos\left(7\frac{y-x}{y+x}\right)\,\mathrm dA=\int_8^9\int_{-u}^u\frac52\cos\left(\frac{7v}u\right)\,\mathrm dv\,\mathrm du$

$=\displaystyle\frac52\int_8^9\frac u7(\sin7-\sin(-7))\,\mathrm du$

$=\displaystyle\frac57\sin7\int_8^9u\,\mathrm du$

$=\displaystyle\frac5{14}\sin7(9^2-8^2)=\boxed{\frac{85}{14}\sin7}$

4 0

3 years ago

When they arrived in Philadelphia, Tyler’s family took a taxi to a museum. The taxi charged $2.70 per mile, and they paid the dr

shtirl [24]

Answer:

5 miles

Step-by-step explanation:

To find how many miles it is from the train station to the museum we first have to subtract the tip from the total fair and you get 13.50 and then you divide 13.50 by 2.70 to get the number of miles and you get 5.

3 0

3 years ago

Write an equation in slope-intercept form for the line with slope -2 and y-intercept 5.

Nana76 [90]

Answer:

y = -2x + 5

Step-by-step explanation:

5 0

3 years ago

Use the properties of logarithms to expand each logarithmic expression as much as possible. Where possible, evaluate logarithmic

seraphim [82]

Answer:

xvdsltoqk73jyeu54344y5eg62iuyeytmemymduememwu

6 0

3 years ago

last week you sold 30,45,50,75 and 80 units each day of the week in that order . On average how many units did you sell per day?

Butoxors [25]

Answer:

56 units

Step-by-step explanation:

add all numbers then divide by 5

30+45+50+75+80 = 280

280/5 = 56

4 0

3 years ago