Ask question

Ask question

All categories

3 years ago

9

What is The answer to this equation -9•(5j+k)

1 answer:

vlada-n [284]3 years ago

5 0

Answer:

-45j -9k

Step-by-step explanation:

You might be interested in

The use of mathematical methods to study the spread of contagious diseases goes back at least to some work by Daniel Bernoulli i

harina [27]

Answer:

a

$y(t) = y_o e^{\beta t}$

b

$x(t) = x_o e^{\frac{-\alpha y_o }{\beta }[e^{-\beta t} - 1] }$

c

$\lim_{t \to \infty} x(t) = x_oe^{\frac{-\alpha y_o}{\beta } }$

Step-by-step explanation:

From the question we are told that

$\frac{dy}{y} = -\beta dt$

Now integrating both sides

$ln y = \beta t + c$

Now taking the exponent of both sides

$y(t) = e^{\beta t + c}$

=> $y(t) = e^{\beta t} e^c$

Let $e^c = C$

So

$y(t) = C e^{\beta t}$

Now from the question we are told that

$y(0) = y_o$

Hence

$y(0) = y_o = Ce^{\beta * 0}$

=> $y_o = C$

So

$y(t) = y_o e^{\beta t}$

From the question we are told that

$\frac{dx}{dt} = -\alpha xy$

substituting for y

$\frac{dx}{dt} = - \alpha x(y_o e^{-\beta t })$

=> $\frac{dx}{x} = -\alpha y_oe^{-\beta t} dt$

Now integrating both sides

$lnx = \alpha \frac{y_o}{\beta } e^{-\beta t} + c$

Now taking the exponent of both sides

$x(t) = e^{\alpha \frac{y_o}{\beta } e^{-\beta t} + c}$

=> $x(t) = e^{\alpha \frac{y_o}{\beta } e^{-\beta t} } e^c$

Let $e^c = A$

=> $x(t) =K e^{\alpha \frac{y_o}{\beta } e^{-\beta t} }$

Now from the question we are told that

$x(0) = x_o$

So

$x(0)=x_o =K e^{\alpha \frac{y_o}{\beta } e^{-\beta * 0} }$

=> $x_o = K e^{\frac {\alpha y_o }{\beta } }$

divide both side by $(K * x_o)$

=> $K = x_o e^{\frac {\alpha y_o }{\beta } }$

So

$x(t) =x_o e^{\frac {-\alpha y_o }{\beta } } * e^{\alpha \frac{y_o}{\beta } e^{-\beta t} }$

=> $x(t)= x_o e^{\frac{-\alpha * y_o }{\beta} + \frac{\alpha y_o}{\beta } e^{-\beta t} }$

=> $x(t) = x_o e^{\frac{\alpha y_o }{\beta }[e^{-\beta t} - 1] }$

Generally as t tends to infinity , $e^{- \beta t}$ tends to zero

so

$\lim_{t \to \infty} x(t) = x_oe^{\frac{-\alpha y_o}{\beta } }$

5 0

3 years ago

You sell 500 shares of Arena Pharmaceuticals (ARNA) at $3.15 . You purchased the stock at $1.28. How much profit did you make?

denis23 [38]

Answer:

Profit = 935

Step-by-step explanation:

Purchase price: 500×1.28=640

Selling price: 500×3.15=1575

Profit: selling price - purchase price = profit

1575 - 640 = 935

Profit = 935

8 0

3 years ago

What is 453-259 with your work bring shown

photoshop1234 [79]

The answer is 194 you have to carry on

5 0

4 years ago

A particular train is 25 feet tall. A model of the train was built with a scale of 4 inches which is equal to 5 feet. How tall i

sergeinik [125]

The answer is 20in. You multiply 4 by 5 because 5x5 is 25 so the answer is 20

3 0

3 years ago

my granola bar recipe calls for 8 2/3ups of pecans and 4 1/3 cups of walnuts. How many cups of nuts are needed in the recipe?

UNO [17]

8 + 4 = 12
1/3 + 2/3 = 1
12 + 1 = 13 cups of nuts.

5 0

4 years ago