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uranmaximum [27]

3 years ago

6

Please write out the expression step by step to show why this is true

1 answer:

Andreyy893 years ago

8 0

(2x+3y)4 hope this helps

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Marine biologists have determined that when a shark detectsthe presence of blood in the water, it will swim in the directionin w

siniylev [52]

Solution :

a). The level curves of the function :

$C(x,y) = e^{-(x^2+2y^2)/10^4}$

are actually the curves

$e^{-(x^2+2y^2)/10^4}=k$

where k is a positive constant.

The equation is equivalent to

$x^2+2y^2=K$

$\Rightarrow \frac{x^2}{(\sqrt K)^2}+\frac{y^2}{(\sqrt {K/2})^2}=1, \text{ where}\ K = -10^4 \ln k$

which is a family of ellipses.

We sketch the level curves for K =1,2,3 and 4.

If the shark always swim in the direction of maximum increase of blood concentration, its direction at any point would coincide with the gradient vector.

Then we know the shark's path is perpendicular to the level curves it intersects.

b). We have :

$\triangledown C= \frac{\partial C}{\partial x}i+\frac{\partial C}{\partial y}j$

$\Rightarrow \triangledown C =-\frac{2}{10^4}e^{-(x^2+2y^2)/10^4}(xi+2yj),$ and

$\triangledown C$ points in the direction of most rapid increase in concentration, which means $\triangledown C$ is tangent to the most rapid increase curve.

$r(t)=x(t)i+y(t)j$ is a parametrization of the most $\text{rapid increase curve}$ , then

$\frac{dx}{dt}=\frac{dx}{dt}i+\frac{dy}{dt}j$ is a tangent to the curve.

So then we have that $\frac{dr}{dt}=\lambda \triangledown C$

$\Rightarrow \frac{dx}{dt}=-\frac{2\lambda x}{10^4}e^{-(x^2+2y^2)/10^4}, \frac{dy}{dt}=-\frac{4\lambda y}{10^4}e^{-(x^2+2y^2)/10^4}$

∴ $\frac{dy}{dx}=\frac{dy/dt}{dx/dt}=\frac{2y}{x}$

Using separation of variables,

$\frac{dy}{y}=2\frac{dx}{x}$

$\int\frac{dy}{y}=2\int \frac{dx}{x}$

$\ln y=2 \ln x$

⇒ y = kx^2 for some constant k

but we know that $y(x_0)=y_0$

$\Rightarrow kx_0^2=y_0$

$\Rightarrow k =\frac{y_0}{x_0^2}$

∴ The path of the shark will follow is along the parabola

$y=\frac{y_0}{x_0^2}x^2$

$y=y_0\left(\frac{x}{x_0}\right)^2$

7 0

3 years ago

Find the measure of the indicated angle to the nearest degree.

makvit [3.9K]

You would do tan<span>Ɵ = 9/12
tan^-1(9/12) = </span><span>Ɵ
</span><span>Ɵ = 36.87 degress
make sure your calculator is in degree mode

</span>

8 0

3 years ago

Read 2 more answers

What is the range of the function?<br> A. (-1,3,5)<br> B. (2,6,8,3,5)<br> C. {3}<br> D. (2,6,8)

Roman55 [17]

Answer:

I think the answer is D. (2,6,8) because if the ones on the right are y - coordinates in the Function then it should be correct. If not sorry

(Range is y - coordinate)

(Domain is x - coordinate)

7 0

3 years ago

The points ????(0,0), ????(−4,1), ????(−3,5), and ????(1,4) are the vertices of parallelogram OABC Is this parallelogram a

gavmur [86]

Answer:

Yes, parallelogram OABC is a rectangle.

Step-by-step explanation:

The vertices of a parallelogram are O(0,0), A(-4,1), B(-3,5) and C(1,4).

A parallelogram is a rectangle if its any two adjacent sides are perpendicular to each other.

product of slopes of two perpendicular lines is -1.

Formula for slope is

$Slope=\dfrac{y_2-y_1}{x_2-x_1}$

Using the formula we get

$m_{OA}=\dfrac{1-0}{-4-0}=-\dfrac{1}{4}$

$m_{AB}=\dfrac{5-1}{-3-(-4)}=-\dfrac{4}{1}=4$

$m_{OA}\times m_{AB}=-\dfrac{1}{4}\times 4=-1$

It means OA is perpendicular to AB.

Since two adjacent sides are perpendicular, therefore the given parallelogram OABC is a rectangle.

6 0

3 years ago

How could you describe this graph?

Musya8 [376]

It is definitely skewed left if thats what you need

6 0

3 years ago

Read 2 more answers