Solve the expression 8x+2y+4

In evaluating a double integral over a region D, a sum of iterated integrals was obtained as follows:

BabaBlast [244]

Answer

$a=0$ , $b=2$

$g_1(x)=\frac{5x}{2}$ , $g_2(x)=7-x$

Step-by-step explanation:

Given that

$\int \int Df(x,y)dA=\int_0 ^5\int _0 ^ {\frac {2y}{5}} f(x,y)dxdy+\int_5^7\int_0^{7-y} f(x,y)dxdy\; \cdots (i)$

For the term $\int_0 ^5\int _0 ^ {\frac {2y}{5}} f(x,y)dxdy$ .

Limits for $x$ is from $x=0$ to $x=\frac {2y}{5}$ and for $y$ is from $y=0$ to $y=5$ and the region $D$ , for this double integration is the shaded region as shown in graph 1.

Now, reverse the order of integration, first integrate with respect to $y$ then with respect to $x$ . So, the limits of $y$ become from $y=\frac{5x}{2}$ to $y=5$ and limits of $x$ become from $x=0$ to $x=2$ as shown in graph 2.

So, on reversing the order of integration, this double integration can be written as

$\int_0 ^5\int _0 ^ {\frac {2y}{5}} f(x,y)dxdy=\int_0 ^2\int _ {\frac {5x}{2}}^5 f(x,y)dydx\; \cdots (ii)$

Similarly, for the other term $\int_5 ^7\int _0 ^ {7-y} f(x,y)dxdy$ .

Limits for $x$ is from $x=0$ to $x=7-y$ and limits for $y$ is from $y=5$ to $y=7$ and the region $D$ , for this double integration is the shaded region as shown in graph 3.

Now, reverse the order of integration, first integrate with respect to $y$ then with respect to $x$ . So, the limits of $y$ become from $y=5$ to $y=7-x$ and limits of $x$ become from $x=0$ to $x=2$ as shown in graph 4.

So, on reversing the order of integration, this double integration can be written as

$\int_5 ^7\int _0 ^ {7-y} f(x,y)dxdy=\int_0 ^2\int _5 ^ {7-x} f(x,y)dydx\;\cdots (iii)$

Hence, from equations $(i)$ , $(ii)$ and $(iii)$ , on reversing the order of integration, the required expression is

$\int \int Df(x,y)dA=\int_0 ^2\int _ {\frac {5x}{2}}^5 f(x,y)dydx+\int_0 ^2\int _5 ^ {7-x} f(x,y)dydx$

$\Rightarrow \int \int Df(x,y)dA=\int_0 ^2\left(\int _ {\frac {5x}{2}}^5 f(x,y)+\int _5 ^ {7-x} f(x,y)\right)dydx$

$\Rightarrow \int \int Df(x,y)dA=\int_0 ^2\int _ {\frac {5x}{2}}^{7-x} f(x,y)dydx\; \cdots (iv)$

Now, compare the RHS of the equation $(iv)$ with

$\int_a^b\int_{g_1(x)}^{g_2(x)} f(x,y)dydx$

We have,

$a=0, b=2, g_1(x)=\frac{5x}{2}$ and $g_2(x)=7-x$ .

3 0

3 years ago

Mountain officials want to know the length of a new ski lift from A to C , as shown in the figure below. They measure angle DAC

Ede4ka [16]

We assume that the hill is represented by points ACD and the ski lift is represented by points BCD. From the description above, points CDB would have an angle of 90 degrees. Then, we would have:

sin (32) = CD / 960
CD = 508.72

tan 32 = 508.72 / AD
AD = 814.13

Therefore, the distance would be 814.13 - 508.72 = 305.4 ft.

4 0

3 years ago

Explain why the hypotenuses of the triangles below have the same slope.

andrew11 [14]

The hypotenuse of the two triangles have the same slope because they are in the same straight line and the slope of a straight line is constatn.

You can prove that in this way:

slope = rise / run = Δy / Δx

For the upper triangle: slope = (4 - 2) / (8 - 4) = 2 / 4 = 1 / 2

For the lower triangle: slope = (-1 - (-5)) / (- 2 - (-10)) = 4 / 8 = 1 / 2

So, this proves that the two slopes are the same: 1 / 2

3 0

4 years ago

The weather in a certain locale consists of alternating wet and dry spells. Suppose that the number of days in each rainy spell

Amiraneli [1.4K]

Answer:

2/9

Step-by-step explanation:

The Poisson’s distribution is a discrete probability distribution. A discrete probability distribution means that the events occur with a constant mean rate and independently of each other. It is used to signify the chance (probability) of a given number of events occurring in a fixed interval of time or space.

In the long run, fraction of time that it rains = E(Number of days in rainy spell) / {E(Number of days in a rainy spell) + E(Number of days in a dry spell)}

E(Number of days in rainy spell) = 2

E(Number of days in a dry spell) = 7

In the long run, fraction of time that it rains = 2/(2 + 7) = 2/9

7 0

4 years ago

What is the volume of the rectangular prism if the length is 3/4 the width is 2/3 and the hight is 1/2

Leno4ka [110]

Multiply it all together 3/4 is 0.75 2/3 is 0.66 1/2 is 0.5 now do in your calculator 0.75+0.66+0.5 and becase everything is in fractions remember that you have to convert your decimal into a fraction your answer is 1 91/100

6 0

4 years ago