The concentration of a drug in the body decreases exponentially after a dosage is given. In one clinical study, adult subjects averaged 14 micrograms/milliliter (mcg/mL) of the drug in their blood plasma 1 hr after a 1000-mg dosage and 3 micrograms/milliliter 4 hr after dosage.
a) Find the value k, and write an equation for an exponential function that can be used to predict the concentration of the drug, in micrograms/milliliter, t hours after a 1000-mg dosage.
b) Estimate the concentration of the drug 3 hr after a 1000-mg dosage.
c) To relieve a fever, the concentration of the drug should go no lower than 4 mcg/mL. After how many hours will a 1000-mg dosage drop to that level?
k = ________(Round to three decimal places as needed.)

Answer:

the answer is 1/14

hope this helps you

9514 1404 393

Answer:

  (a)  1/14

Step-by-step explanation:

Fractions are multiplied by multiplying numerators and denominators. They are reduced by cancelling common factors. When a product has an even number of minus signs, it is positive.

  [tex]\left(-\dfrac{3}{7}\right)\cdot\left(-\dfrac{1}{6}\right)=\dfrac{(-3)(-1)}{7\cdot6}=\dfrac{3}{7\cdot2\cdot3}=\dfrac{1}{7\cdot2}=\boxed{\dfrac{1}{14}}[/tex]

Answer:

28 square units.

Step-by-step explanation:

This is a rectangle with sides (7 - (-7) and (5 - 3)

= 14 by 2

= 28 unit^2.

The last part answers the first part for you, just look at the y-values.

In other words:

A' (-8, 2)

B' (-4, 3)

C' (-2, 8)

D' (-10, 6)

Explanation:

When you reflect any point over the x-axis, the y-value of the ordered pair is going to change.

This makes sense especially considering that the x-axis is horizontal, so the only way you could cross is to move up or down. If you were to move left or right, you'd only be able to cross the y-axis, since it's vertical.

Now for the last part, as I mentioned above, if you are reflecting across the y-axis, the x-values of the ordered pair is going to change.

A'' (8, 2)

B'' (4, 3)

C'' (2, 8)

D'' (10, 6)

Take note that the only thing that changes for the respective value is its sign, while the number itself stays the same.

Answer:

Parallel

Step-by-step explanation:

Because of interior alternate angles

Angle ARS and Angle BRS are Interior alternate angles in this case ..

Answer:

The (y^2 ) or (y^–2) It is not clear, I solved it in both ways (y^2) and (y^-2) .^_^

[tex] - 7 {x }^{2} - 5 + {y}^{2} \\ - 7( { - 2}^{2} ) - 5 + {4}^{2} \\ - 7( - 4) - 5 + 16 \\ 28 - 5 + 16 \\ = 39[/tex]

_______o_____o_______

[tex] - 7 {x }^{2} - 5 + {y}^{ - 2} \\ - 7( { - 2}^{2} ) - 5 + {4}^{ - 2} \\ - 7( - 4) - 5 + \frac{1}{16} \\ 28 - 5 + \frac{1}{16} \\ = 23.06[/tex]

I hope I helped you^_^

A rectangle can be constructed using a straightedge, and a setsquare or compass

Please find attached the drawing of rectangle ABCD

The steps to construct the rectangle ABCD are as follows:

Question:

The missing part of the question is the name of the rectangle = ABCD

The given parameters are;

The length of the side AB = 8 cm

The length of the diagonal of the rectangle ABCD = AC = 10 cm

The steps to construct a rectangle are;

h² = [tex]\overline{AC}[/tex]² - [tex]\overline{AB}[/tex]²

∴ h² = 10² - 8² = 36

h = √36 = 6

h = 6 cm = The length of the sides [tex]\mathbf{\overline{AD}}[/tex] and [tex]\mathbf{\overline{CB}}[/tex]

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Answer: 0.0228

Step-by-step explanation:

please check photo explanation

The probability that the sample mean will be greater than 22.2 ounces will be equal to 0.0228

Probability is calculated as the proportion of favorable events to all potential scenarios of an event. The proportion of positive results, or x, for an experiment with 'n' outcomes can be expressed.

As per the given values in the question,

[tex]\mu_x[/tex] = 22

σ(x) = σ/√n

= 1/√100

σ(x) = 0.1

P(x>22.2) = 1- P(x<22.2)

= 1- P(x × μ(x))/ σ(x) < (22.2 - 22)/0.1

1 - P (z < 2.00)

1- 0.9772

= 0.0228

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Step-by-step explanation:

Hi there!

Please see attached picture for your answer.

Hope it helps!

We need to find the amount of money Janet invested in 10 years to yield 7425 EUR

She invested EUR 21,214.29

Simple interest = P × R × T

Where,

P = principal = ?

R = interest rate = 3.5% = 0.035

T = Time = 10 years

Simple interest = 7425 EUR

Simple interest = P × R × T

7425 = p × 0.035 × 10

7425 = p × 0.35

7425 = 0.35p

Divide both sides by 0.35

P = 7425 / 0.35

= 21,214.285714285

Approximately,

P = EUR 21,214.29

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Answer

3y(5x+1)

Step-by-step explanation:

9*(5x+1)/3y

3(5x+1)y

Answer:

Step-by-step explanation:

sum: 5x + 1

factor: 3 which divides into 9 evenly

quotient: the answer to division: 9(5x + 1)/(3y) = 3(5x +1)/y

coefficent: this depends on what you have been told. In my day, there were two kinds of coefficents

numerical: 5 and 3

literal: x and y

Answer:

It is a direct variation...

The price of flour does not increase or decrease the

more that you purchase (no discount for large purchases)

(1,0.5) means that a pound of flour costs 50

40 pounds would cost $20

Step-by-step explanation:

[tex]\\ \sf\longmapsto f(-1)[/tex]

[tex]\\ \sf\longmapsto -2x^3+3x^2-22[/tex]

[tex]\\ \sf\longmapsto -2(-1)^3+3(-1)^2-22[/tex]

[tex]\\ \sf\longmapsto -2(-1)+3(1)-22[/tex]

[tex]\\ \sf\longmapsto 2+3-22[/tex]

[tex]\\ \sf\longmapsto 5-22[/tex]

[tex]\\ \sf\longmapsto -17[/tex]

Answer:

i is defined as the square root of -1.

i^2 = -1

i^3 = -i

i^4 = 1

Following the pattern, we see that i^40 = 1, so i^38 is two above, or equal to -1.

So, i^38 = -1.

Let me know if this helps!

Here we have a problem of maximization and quadratic equations.

The unit prize that maximizes the revenue is $1,500, and the maximum revenue is $18,000.

We know that the revenue equation is:

R(P) = - 8p^2 + 24,000p

Where the variable p is the price.

Now we want to find the value of p that maximizes the revenue.

To do it, we can see that the revenue equation is a quadratic equation with a negative leading coefficient.

This means that the arms of the graph will go downwards, then the maximum point of the graph will be at the vertex.

Remember that for an equation like:

y = a*x^2 + b*x+ c

The x-value of the vertex is at:

x = -b/(2*a)

Then for the equation:

R(P) = - 8p^2 + 24,000p

The vertex is at:

p = -(24,000)/(2*-8) = 1,500

The value of p that maximizes the revenue is p = $1,500

To get the maximum revenue, we need to evaluate the revenue equation in that p value.

R(1,500) =  - 8*(1,500)^2 + 24,000*1,500 = 18,000

And the revenue equation is in dollars, then the maximum revenue is 18,000 dollars.

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p = 1500  $    the unit price

R(p) = 18000000 $ maximum revenue

We will use two different procedures to calculate the maximum revenue.

That is equivalent to solve the problem and after that to test the solution

The first one is:

R(p) = - 8*p² + 24000*p

we realize that R(p) is a quadratic function ( a parabola) of the form:

y = a*x² + b*x + c    ( c = 0 in this case)

We also know that  as the coefficient of p² is negative the parabola opens downwards then the vertex is a maximum value for R(p), and the x coordinate of p is:

x = p =  - b/2*a   then by substitution

p = - ( 24000)/ 2 ( - 8)

p = 1500  $   and for that value of p

R(p) = - 8 ( 1500)² + 24000* (1500)  = - 18000000 + 36000000

R(p) = 18000000 $

The second procedure is solving with the help of derivatives.

R(p) =  - 8*p² + 24000*p

Tacking derivatives on both sides of the equation we get:

R´(p) = -16p  +  24000

If R´(p) = 0    then    -16p  +  24000 = 0

p = 24000/ 16         p  =  1500

if we check for the second derivative

R´´(p) = -16          -16 < 0  therefore there is a maximum value for R(p) when p = 1500, and that value is:

By substitution in R(p)

R(p) = -8 *(1500)² + 24000* 1500

R(p) =  - 18000000 + 36000000

R(p) = 18000000 $

Answer:

4206 is the answer of this question

Answer:

I think it will help you a lot.

The answer is simply just a+b.

Solution:

log10^6=log10^2+log10^3

Since log10^2=a and log10^3=b,

The answer is a+b.

I think that the answer is a+b.

If y = y(x), then the derivative with respect to x is dy/dx. Differentiating both sides of the given equation gives

d/dx [4x ² + y ²] = d/dx [36]

8x + 2y dy/dx = 0

2y dy/dx = -8x

dy/dx = -4x/y

The turning points of the curve, taken as a function of x, are those points where the derivative vanishes.

-4x/y = 0   ===>   x = 0

This value of x corresponds to two points on the curve,

4×0² + y ² = 36   ===>   y ² = 36   ===>   y = ±6

So there are two turning points, (0, -6) and (0, 6).

Step-by-step explanation:

A=140sq. units

Step-by-step explanation:

ABCD

A=13

B=15

C=14

D=20

C=14×14

=196sqr.units

first we shall learn the rules.when numbers with same sign are divided it gives pisitive sign but, when numbers of different signs are divided it gives negetive sign.

here,

7. (-154) ➗ (-14) =11

11. (-40) ➗10=-4

15. 90 ➗ (-15)=-6

16. 108 ➗ (-9)=-12

17. (-48) ➗ (-6)=8

18. (-105) ➗ 7=-15

hope it helps you..........

Answer: r = 50 miles/h

Step-by-step explanation:

Let r be the rate of average speed.

Then

r = D/t

r = 150/3

r = 50 miles/h

please click thanks and mark brainliest if you like :)

Answer:

The inverse is x/3 -1

Step-by-step explanation:

y = 3x+3

To find the inverse, exchange x and y

x = 3y+3

Solve for y

x-3 =3y+3-3

x-3 = 3y

Divide by 3

x/3 - 3/3 = 3y/3

x/3 -1 = y

The inverse is x/3 -1

Answer:

Cube C

Step-by-step explanation:

[tex]{ \sf{because \: it \: is \: identical}}[/tex]

Answer:

Step-by-step explanation:

87°32' = 86°92'

(86°92')/2 = 43°46'

B = 13/(16cos(43°46')) = 1.125

Answer:

Step-by-step explanation:

Answer:

There is a   min     value of   376     located at (x,y) =   (9,7)  

============================================================

Explanation:

Solve the second equation for y

x+y = 16

y = 16-x

Then plug it into the first equation

f(x,y) = 3x^2+4y^2 - xy

g(x) = 3x^2+4(16-x)^2 - x(16-x)

g(x) = 3x^2+4(256 - 32x + x^2) - 16x + x^2

g(x) = 3x^2+1024 - 128x + 4x^2 - 16x + x^2

g(x) = 8x^2-144x+1024

The positive leading coefficient 8 tells us we have a parabola that opens upward, and produces a minimum value (aka lowest point) at the vertex.

Let's compute the derivative and set it equal to zero to solve for x.

g(x) = 8x^2-144x+1024

g ' (x) = 16x-144

16x-144 = 0

16x = 144

x = 144/16

x = 9

The min value occurs when x = 9. Let's find its paired y value.

y = 16-x

y = 16-9

y = 7

The min value occurs at (x,y) = (9,7)

Lastly, let's find the actual min value of f(x,y).

f(x,y) = 3x^2+4y^2 - xy

f(9,7) = 3(9)^2+4(7)^2 - 9*7

f(9,7) = 376

The smallest f(x,y) value is 376.

9514 1404 393

Answer:

  221 hours

Step-by-step explanation:

The population is given by the exponential equation ...

  population = (initial value) × (1 +growth rate)^t

where the units of t are the same as the units of growth rate.

This lets us write ...

  p(t) = 5000×1.01^t

We want this to be 45000, so ...

  45000 = 5000×1.01^t

  9 = 1.01^t . . . . . . . . . . . . divide by 5000

  log(9) = t×log(1.01) . . . . take logs

  t = log(9)/log(1.01) ≈ 220.8

It will take about 221 hours for the population to reach 45000.

Answer:

The answer is A

Step-by-step explanation:

The answer needs to be in slope-intercept form or y=mx+b because the amount of carpet being cleaned every minute is a constant decrease of 9 square feet.

So our b value (or how much carpet cleaned at 0 minutes) is 220

And our m value (or slope or how much carpet is being cleaned every minute) is 9

So if we plug the variables with the tangible numbers we get A(t) = -9x+220 or A(t) = 220-9x.

provided by gauth math

Answer:

Step-by-step explanation:

P = 2(3x-20) + 2(2x+4) = (6x-40) + (4x+8) = 10x-32

The required perimeter of the playground is 10x-32.

The length of the playground measures (3x-20) metres.
The width of the playground measures (2x+4) metres.

Perimeter, is the measure of the figure on its circumference.

The Required perimeter is for the playground is given by
= 2(3x-20) + 2(2x+4)

= 10x-32

Thus the required perimeter of the playground is 10x-32.

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The probability that he receives an invitation to work in a bank given that he defends his diploma excellently is [tex]\mathbf{0. \overline 6}[/tex]

The reason for the above probability value is as follows;

The known parameters are;

The probability that a graduate of the Faculty of Finance will defend the diploma excellently, P(A) = 0.6

The probability that he will defend perfectly and receive an invitation to work at a bank, P(A∩B) = 0.4

The unknown parameter is;

The probability that the student will receive an invitation from the bank given that the student defend the diploma excellent, [tex]\mathbf {P(B \ | \ A)}[/tex]

The process;

[tex]\mathbf{ P(B \ | \ A)}[/tex] is found using the conditional probability formula as follows;

[tex]\mathbf {P(B \ | \ A) = \dfrac{P(A \cap B) }{P(A)}}[/tex]

Plugging in the values, we get;

[tex]P(B \ | \ A) = \dfrac{0.4 }{0.6} = \dfrac{2}{3} = 0. \overline 6[/tex]

The probability that the student will receive an invitation from the bank given that the student defend the diploma excellent, [tex]P(B \ | \ A)[/tex] = [tex]\mathbf {0. \overline 6}[/tex]

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