7. A particular compound decays according to the equation y = ae-0.0736t, where tis in days. Find the
half-life of this compound.
a. about 9.1 days b. about 9.4 days
c. about 6.8 days d. about 7.4 days

Answers

Answer 1

Answer:

b. about 9.4 days

Step-by-step explanation:

Amount of the compound:

The amount of the compound after t days is given by the following equation:

[tex]y(t) = ae^{-0.0736t}[/tex]

The initial amount is:

[tex]y(0) = a[/tex]

Half-life:

t for which [tex]y(t) = 0.5a[/tex]. So

[tex]y(t) = ae^{-0.0736t}[/tex]

[tex]0.5a = ae^{-0.0736t}[/tex]

[tex]e^{-0.0736t} = 0.5[/tex]

[tex]\ln{e^{-0.0736t}} = \ln{0.5}[/tex]

[tex]-0.0736t = \ln{0.5}[/tex]

[tex]t = -\frac{\ln{0.5}}{0.0736}[/tex]

[tex]t = 9.42[/tex]

So about 9.4 days, and the answer is given by option b.


Related Questions

Solve the following problems. Choose the letter of the correct answer. (Show your complete solutions.)

5.) If the length of the two sides of an isosceles triangle are 3 cm and 7 cm, then what must be the length of the third side?

A. 3cm B. 10 cm C. 14 cm D. 7 cm​

Answers

:1

i didnt understand the question because of my English sorry

:2

we all know that the total of degrees is 180 so 70+70=140

180-140=40

so the answer is 40

3:

we have a figure with 4 angle so the total of degrees is 360 so the answer is 126

4:

the answer most be 50 becuse we have a Special degree witch always equal 90 if we have recatngle so

x+40=90

X=50 the answer and if you want to try again choose the second one

2x-10=90

2x=100

X=50 same answe you see

5:

in this quastion i searched and find alot of answers any way

its should be 7 or 3 but the correct answer in my opinion its 7

its shows in the picture i sent hopefully its helpful to you i will try to translate the first quastion and sent it to you

S(x)=5x+5
T(x)=_3x +4

The value of t(s(2))

Answers

Answer:

Step-by-step explanation:

This is a composite function, in which we will first evaluate the s function at a value of 2, then we will use that value in the t function.

s(2) = 5(2)+ 5 so

s(2) = 15. Now we evaluate the t function at 15:

t(15) = 3(15) + 4 so

t(15) = 49

ANSWER PLEASE i need help i will mark brainliest

Answers

Answer:

let the two no. be x and y.

their sum

x+y=-11

x=-11-y.....[I]

and difference

x-y=41

x=41+y......[ii]

equating equation I and ii

we get

-11-y=41+y

-11-41=y+y

-52=2y

y=-52/2

y=-26

now

substituting value of y in equation I.

we get

x=-11-(-26)=-11+26=15

The two no. is 15 and -26.

What is the approximate lateral surface area of the cylinder?
9 cm
2 cm

Answers

Answer:

138 is closest to the  Lateral surface which is 113.097

Step-by-step explanation:

what shapes have 2 pairs of parallel sides? Choose all that arw correct.​

Answers

Answer:

can we see the options please

square, rectangular, rhombus

solve these equations, show all your work x/2=20

Answers

Answer:

x = 40

Step-by-step explanation:

x/2 = 20

x/2(2) = 20(2)

x = 40

let f(x)=-2x-1 and g(x)=x^2+4 find (f o g) (1)

Answers

αηѕωєя

[tex]fog(x)=f(g(x)) \\ \\ \\ =2.(4-x^2)-1 \\ \\ \\ = -2x^2+7 \\ \\ \\ [/tex]

Does anyone know how to
Solve this

Answers

Answer:

53.4 cm^2

Step-by-step explanation:

rhombus's have the same formula as a square (B*H)

8.9*6 = 53.4 cm^2

30 points!!!!!! please help quick!!!

Answers

Answer: The first picture is A an the secund Picture is D

Step-by-step explanation:

i hope this help

Arianna earns $15 for doing yard work for 3 hours. If Arianna charges at the same rate, how many hours will it take her to
earn $35? hours

Answers

Answer:

7 hours

Step-by-step explanation:

15 dollars +15 dollars 30 dollars=2 hours. 5 dollars left 15 divided by 3, 5 dollars. 3 divided by 3 = 1 so 1 hours is 5 dollars. My explaining is not good.

Answer: 7 hours

Step-by-step explanation:

She earns 5 dollars per hour because 5x3=15

and then you do 15x2=30

then 3x2=6

then just add 1 to 6

6+1=7

so there's your answer

7 hours

Find the volume of the pyramid. v=

Answers

Answer:

240 mi^3

Step-by-step explanation:

Base area = length x width = 10 x 8 = 80 mi^2

V = (base area x height)/3 = (80 x 9)/3 = 240 mi^3


HELP QUICK ROUND EACH VALUE TO THE NEAREST TENTH

Answers

Hmm I don’t know.... I really don’t know.

Does anyone know how to simplify this expression? I know it has to do with properties of summation and special summation rules but I can’t quite figure it out.

Answers

Answer:     -n/(n+1)

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

Explanation:

Let's expand this out up to say n = 6 terms

I'll write the summation in such a way that each (1/(k+1) - 1/k) grouping will get its own row. Each row has the same value of k.

If we plug in k = 1 through k = 6, but not evaluate just yet, we will have this:

1/(1+1) - 1/1

1/(2+1) - 1/2

1/(3+1) - 1/3

1/(4+1) - 1/4

1/(5+1) - 1/5

1/(6+1) - 1/6

All I've done so far is replace k with 1 through 6. Again, each row represents a different k value. Each row has the general format 1/(k+1)-1/k.

Let's simplify everything in the first column.

So the (1+1) turns into 2, the (2+1) turns into 3, and so on.

Doing that leads to...

1/2 - 1/1

1/3 - 1/2

1/4 - 1/3

1/5 - 1/4

1/6 - 1/5

1/7 - 1/6

Then note how we have the cancellations shown in the diagram below. The color coding shows how the terms pair up to cancel out. By "cancel out", I mean specifically that the fractions add up to 0. Eg: 1/2 + (-1/2) = 0.

Nearly everything cancels out. The only things left after the dust settles is the -1/1 in the first row and the 1/7 in the bottom row. This evaluates to 1/7-1/1 = 1/7 - 7/7 = (1-7)/1 = -6/7

If you were to try this with n = 7, then you should find that again nearly everything cancels but the fractions -1/1 and 1/8. Then 1/8 - 1/1 = -7/8.

For n = 8, you should end up with 1/9 - 1/1 = -8/9.

You can probably see the pattern.

A conjecture is that the answer is -n/(n+1). The general proof of this isn't too tricky. Simply follow the same ideas as mentioned above. Expand out a few terms and see how things cancel out. You'll find that everything cancels except for the -1/1 in the first row and the 1/(n+1) just one term before the very end. Then we can say:

1/(n+1) - 1/1

1/(n+1) - (n+1)/(n+1)

(1-(n+1))/(n+1)

(1-n-1)/(n+1)

-n/(n+1)

If we tried n = 6, then we find,

-n/(n+1) = -6/(6+1) = -6/7

which was the result we found earlier when we added the first n = 6 terms of this series. Trying out n = 7 should lead to -n/(n+1) = -7/8, and so on.

In ΔWXY, the measure of ∠Y=90°, YX = 40, XW = 41, and WY = 9. What ratio represents the cosine of ∠W?

Answers

Answer:

[tex]\cos{W} = \frac{9}{41}[/tex]

Step-by-step explanation:

Cosine of an angle:

The cosine of an angle, in a right triangle, is the length of the side adjacent to this angle divided by the hypotenuse.

Length of the largest side:

The length of the largest side is 41, that is, the hypotenuse is 41. The hypotenuse is XW.

WY = 9.

This means that the length of the adjacent side to angle W is 9.

What ratio represents the cosine of ∠W?

Adjacent side has length 9, hypotenuse has length 41. So

[tex]\cos{W} = \frac{9}{41}[/tex]

A) -198+(-32) ayuda porta
B)-99+(-12)

Answers

Answer:

A) -230

B) -111

Step-by-step explanation:

A negative plus a negative is a negative

- + - = -

Does anyone what to talk. I need someone to talk to pls.

Answers

Answer: Sure. HRU?

Step-by-step explanation:

Answer:

hey mama hyb ?

Step-by-step explanation:

A right triangle is removed from a rectangle to create the shaded region shown below. Find the area of the shaded region. Be sure to include the correct unit in your answer.

Answers

Answer:

57m2

Step-by-step explanation:

What is the difference between simplifying radicals and estimating its value?

Answers

Answer:

Simplifying radicals is the process of manipulating a radical expression into a simpler or alternate form. Generally speaking, it is the process of simplifying expressions applied to radicals.

Estimation (or estimating) is the process of finding an estimate, or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available.

Step-by-step explanation:

The radical symbol represents the root of a number and is read as x radical n or the nth root of x.

What is a radical?

The symbol " that expresses a number's root is known as radical, and it is read as x radical n or the nth root of x. The horizontal line that surrounds the number is known as the vinculum, and the number beneath it is known as the radicand. The index or degree is the number n written before the radical.

The process of transforming a radical expression into a simpler or alternate form is known as simplifying radicals. In general, it is the process of simplifying expressions that are applied to radicals.

Estimation (or estimating) is the process of determining an estimate, or approximation, which is a value that can be used for a specific purpose despite the fact that the input data may be incomplete, uncertain, or unstable. The value is still useful because it is based on the best available information.

To know more about radicals follow

https://brainly.com/question/28519153

#SPJ2

What is the value of (5 2– 10) ÷ 5 × 2 3 ?

CORRECT ANSWER PLEASE?!!

Answers

Answer:

210

Step-by-step explanation:

(52-10)

42÷5

8.4×25=210

Answer:

BEODMASS

( 52 - 10 ) ÷ 5 × 23

42÷5 ×23

8.4 x 23

193.2

if x=-4 and y=3 what is the value of x-3y^2

a: -13
b: -31
c: -23
d: -85​

Answers

Answer:

b -31

Step-by-step explanation:

Step-by-step explanation:

x-3y²4-3×3²4-27-23

hope it helps

stay safe healthy and happy..

Question 10 (2 points)
A square table 4 feet on each side has two drop leaves, each a semicircle 4 feet in diameter.
Find the area of the table with and without the drop leaves.
1) With Drop Leaves (Semicircles are attached to table) =
ft. 2
2) Without Drop Leaves (Semicircles are not attached to table)
ft 2
4 ft
|4ft

Answers

Answer:

Area of table with leaf = 28.56 feet²

Area of table without leaf = 16 feet²

Step-by-step explanation:

Given:

Side of square table = 4 feet

Diameter of side leaf = 4 feet

Number of semicircle leaf = 2

Find:

Area of table without leaf

Area of table with leaf

Computation:

Area of square = Side x Side

Area of table without leaf = 4 x 4

Area of table without leaf = 16 feet²

Radius of side leaf = Diameter of side leaf / 2

Radius of side leaf = 4 / 2

Radius of side leaf = 2 feet

Area of table with leaf = Area of table without leaf + 2[πr²/2]

Area of table with leaf = 16+ 2[πr²/2]

Area of table with leaf = 16+ (3.14)(2)²

Area of table with leaf = 16+ (3.14)(4)

Area of table with leaf = 16+ 12.56

Area of table with leaf = 28.56 feet²

what is the area of the cylinder rounded to the nearest whole number

Answers

Answer:

the area is 207

Step-by-step explanation:

The equation to solve the area of a cylinder is A=2πrh+2πr^2

The radius is the length from the outside to the center, 6 is the diameter so we could half that to get the radius, 3 and height is 8

A=2*3.14*3*8+2*3.14*3^2

A=6.28*3*8+6.28*9

A=18.84*8+56.52

A=150.72+56.52

A=207.24

207.24 rounded to the nearest whole number is 207 so your area is 207

Please show steps, 100 points and Brainliest
Convert vertex form f(x)=(x+2)^2-25 to factored form.

Answers

Answer:

f(x)=x^2+4x-21

Step-by-step explanation:

Answer:

f(x) = (x + 7)  (x - 3)

Step-by-step explanation:

f(x)=(x+[tex]2)^{2}[/tex]-25

(x + 7) (x - 3) we put the 2 x's because of the (x+2)^2

now the + 7 and - 3, multiply the 2 numbers = -21 then use those 2 in

(x+2)^2 to add for the answer = -25

Evaluate - 15.85 + y for the following values of y.
value of y value of expression
-32.1 -47.95
-63.06
-84.703
-8.115

Answers

Answer:

-78.91  -100.553  -23.965

Step-by-step explanation:

-15.85 - 63.06 = -78.91

-15.85 -84.703 = -100.553

-15.85 -8.115 = -23.965

Find the equation of the linear function represented by the table below in slope-
intercept form.

Answers

9514 1404 393

Answer:

  y = -4x -2

Step-by-step explanation:

The slope is given by the formula ...

  m = (y2 -y1)/(x2 -x1)

  m = (-10 -10)/(2 -(-3)) = -20/5 = -4

__

The y-intercept is given by ...

  b = y1 -m(x1)

  b = 10 -(-4)(-3) = 10 -12 = -2

Then the slope-intercept equation is ...

  y = mx +b

  y = -4x -2

Please help me. 20 POINTS

Answers

Answer:

could you please also post what the choosing options are and then ill edit this and do it again

Step-by-step explanation:

) Which expressions are equivalent to 35? Choose ALL that apply.
9.27
81.3
3.5
3.3.3.3.3
9.9

Answers

Answer:

[tex](a)\ 9 * 27[/tex]

[tex](b)\ 81 * 3[/tex]

[tex](d)\ 3*3*3*3*3[/tex]

Step-by-step explanation:

Given

[tex]3^5[/tex]

Required

Select equivalent expressions

[tex](a)\ 9 * 27[/tex]

Express as exponents

[tex]9 * 27 = 3^2 * 3^3[/tex]

Apply law of indices

[tex]9 * 27 = 3^{2+3[/tex]

[tex]9 * 27 = 3^{5[/tex]

[tex](b)\ 81 * 3[/tex]

Express as exponents

[tex]81 * 3 = 3^4 * 3[/tex]

Apply law of indices

[tex]81 * 3 = 3^{4+1[/tex]

[tex]81 * 3 = 3^5[/tex]

[tex](c)\ 3*5[/tex]

Solve

[tex]3*5 = 15[/tex]

[tex](d)\ 3*3*3*3*3[/tex]

From calculator, we have

[tex]3*3*3*3*3=243[/tex]

Express as exponents

[tex]3*3*3*3*3=3^5[/tex]

[tex](e) 9 * 9[/tex]

Express as exponents

[tex]9 * 9= 3^2 * 3^2[/tex]

Apply law of indices

[tex]9 * 9= 3^{2+2[/tex]

[tex]9 * 9= 3^4[/tex]

Hence, a, b and d are true

According to a recent study, the average American household spends $1,700 on clothing per year, with a standard deviation of $530. What percent of households spend less than $1170 per year, based on this data?

Answers

Answer:

$3,220

Step-by-step explanation:

Add

PLEAAE HELP Tiffany practices her guitar for hour each day. How many hours does she practice in 7 days? Make an equation to solve the problem.​

Answers

Answer:

7n

Step-by-step explanation:

Let :

The number of hours of practice per day = n

The number of practice hours in 7 days can be calculated thus :

Number of hours of practice per day * number of days

(n * 7) = 7n

Question 16 of 98
In which pair do both decimals represent rational numbers?
O A. 9.0032812373025549382... and 0.12333...
B. 9.0032812373025549382... and 0.115
C. 0.115 and 0.12333...
D. 3.10382947305718274... and 0.123
SUBMIT

Answers

the answer would be b

Answer:

C

Step-by-step explanation:

C. Since .12333 has a repeating character and .115 has a definitive end, they are both rational

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