All categories

3 years ago

Can somebody please help fast?

Mathematics

1 answer:

diamong [38]3 years ago

6 0

Answer: C

Explanation: one Y goes to one X.

You might be interested in

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

What is f(2) = 2x -6

Dennis_Churaev [7]

Answer:

f(2) = -2

Step-by-step explanation:

f(2) = 2x - 6

f(2) = 2(2) - 6

f(2) = 4 - 6

f(2) = -2

4 0

3 years ago

3^sqrt -64w^12<br><img src="https://tex.z-dn.net/?f=%20%5Csqrt%5B3%5D%7B%20-%2064w%5E%7B12%7D%7D%20" id="TexFormula1" title=" \s

Agata [3.3K]

-64=(-4)³, w^12=(w^4)³
the result is -4w^4

7 0

3 years ago

The following two-way table shows the data for the students of two different grades in a school:

Alenkasestr [34]

There are 18 students in Grade 7, 10 are in band, so 10/18 = 0.56 are in band.

There are 12 students in Grade 8, 10 are in band, so 10/12 = 0.83 are in band.

Students in Grade 8 are more likely to be members of the band.

8 0

3 years ago

Read 2 more answers

Which of the scatter plots below shows the most accurate line of best fit?

Marina86 [1]

I think its letter b

3 0

2 years ago