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Y_Kistochka [10]
3 years ago
15

Researchers recorded that a certain bacteria population declined from 800,000 to 500,000 in 6 hours after the administration of

medication. At this rate of decay, how many bacteria would there have been at 24 hours? Round to the nearest whole number
Mathematics
1 answer:
kupik [55]3 years ago
5 0

Answer:

We can assume that the decline in the population is an exponential decay.

An exponential decay can be written as:

P(t) = A*b^t

Where A is the initial population, b is the base and t is the variable, in this case, number of hours.

We know that: A = 800,000.

P(t) = 800,000*b^t

And we know that after 6 hours, the popuation was 500,000:

p(6h) = 500,000 = 800,000*b^6

then we have that:

b^6 = 500,000/800,000 = 5/8

b = (5/8)^(1/6) = 0.925

Then our equation is:

P(t) = 800,000*0.925^t

Now, the population after 24 hours will be:

P(24) = 800,000*0.925^24 = 123,166

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What is 99.96 rounded to the nearest tenth​
nirvana33 [79]

Answer:

It is 100. You round the 6 to the 9 which makes the 9 round the 99 which makes it 100.

3 0
4 years ago
Need help with special right triangles
hjlf

Step-by-step explanation:

For solving this, it's important to know basic trigonometric functions:

sin = opposite side / hypotenuse

cos = adjacent side / hypotenuse

tan = opposite side / adjacent side

It's also important to know that it is necessary to know their values for special right triangles and angles of 30°, 45° and 60°

1. We are given angle if 45° and its adjacent side of 13. We want to know the opposite side (x) and hypotenuse (y). So:

tan = opposite side / adjacent side

tan 45 = x / 13

1 = x / 13

x = 13

Remember that tangent of 45° angle is 1.

We found the opposite side to be also 13.

To find y we can use:

sin = opposite side / hypotenuse

sin 45 = 13 / y

(√2)/2 = 13 / y

y = 13√2

Important to remember, sin 45 and cos 45 are (√2)/2

2. We are given 45° angle and hypotenuse of 30. We need to find opposite side (x) and adjacent side (y).

sin = opposite side / hypotenuse

sin 45 = x / 30

(√2)/2 = x / 30

x = 15√2

Also:

cos = adjacent side / hypotenuse

cos 45 = y / 30

(√2)/2 = y / 30

y = 15√2

We can conclude that in the right triangle, when angle is 45°, opposite and adjacent sides are equal.

3. We are given angle of 60° and adjacent side of 3. We need to find opposite side (y) and hypotenuse (x).

cos = adjacent side / hypotenuse

cos 60° = 3 / x

1/2 = 3 / x

x = 6

Note that cos 60° equals 1/2.

sin = opposite side / hypotenuse

sin 60° = y / 6

(√3)/2 = y / 6

y = 3√3

Note that sin 60° equals (√3)/2.

4. We are given angle of 30° and hypotenuse of 34. We need to find opposite side (y) and adjacent side (x).

sin = opposite side / hypotenuse

sin 30° = y / 34

1/2 = y / 34

y = 17

Note that sin 30° equals to cos 60° equals 1/2.

cos = adjacent side / hypotenuse

cos 30° = x / 34

(√3)/2 = x / 34

x = 17√3

Remember that cos 30° equals to sin 60° which is (√3)/2.

5. We are given an angle of 45° and hypotenuse of 10√2. We need to find the opposite side (y) and adjacent side (x).

sin = opposite side / hypotenuse

sin 45° = y / 10√2

(√2)/2 = y / 10√2

y = 10

To save time, we already said that opposite and adjacent sides are equal in right triangle with 45° angle, so x = y = 10.

6. We are given angle of 60° and opposite side of 25√3. We need to find adjacent side (y) and hypotenuse (x).

sin = opposite side / hypotenuse

sin 60° = 25√3 / x

(√3)/2 = 25√3 / x

x = 50.

tan = opposite side / adjacent side

tan 60° = 25√3 / y

√3 = 25√3 / y

y = 25.

Remember that tangent of 60° angle is √3.

7. We are given angle of 45° and hypotenuse of 2√14. We need to find adjacent side (x) and opposite side (y).

cos = adjacent side / hypotenuse

cos 45° = x / 2√14

(√2)/2 = x / 2√14

x = √28

Again, adjacent and opposite sides are equal in 45° right triangle, so x = y = √28.

8. We are given an angle of 30° and an adjacent side of 24. We need to find the opposite side (y) and hypotenuse (x).

tan = opposite side / adjacent side

tan 30° = y / 24

(√3)/3 = y / 24

y = 8√3

sin = opposite side / hypotenuse

sin 30° = 8√3 / x

1/2 = 8√3 / x

x = 16√3

Note that tan = sin/cos, so tan 30° = sin 30° / cos 30°

tan 30° = 1/2 / (√3)/2 = (√3)/3

I'm showing you this, so you don't have to memorize tan for special angles, you can find it from sin and cos.

9. We are given an angle of 60° and hypotenuse of 22√3. We need to find the opposite side (y) and adjacent side (x).

sin = opposite side / hypotenuse

sin 60° = y / 22√3

(√3)/2 = y / 22√3

y = 33

cos = adjacent side / hypotenuse

cos 60° = x / 22√3

1/2 = x / 22√3

x = 11√3

10. We are given an angle of 30° and the opposite side of √6. We need to find the adjacent side (x) and hypotenuse (y).

sin = opposite side / hypotenuse

sin 30° = √6 / y

1/2 = √6 / y

y = 2√6

tan = opposite side / adjacent side

tan 30° = √6 / x

(√3)/3 = √6 / x

x = √18

11. We are given an angle of 45° and an adjacent side of √10. We need to find the opposite side (x) and hypotenuse (y).

In this triangle opposite and adjacent sides are equal (45° angle), so x = √10

sin = opposite side / hypotenuse

sin 45° = √10 / y

(√2)/2 = √10 / y

y = √20 = 2√5

12. We are given an angle of 60° and the opposite side of 4√21. We need to find the adjacent side (x) and hypotenuse (y).

sin = opposite side / hypotenuse

sin 60° = 4√21 / y

(√3)/2 = 4√21 / y

y = 8√7

tan = opposite side / adjacent side

tan 60° = 4√21 / x

√3 = 4√21 / x

x = 4√7

13. Now things get a little trickier. We are given an angle of 30° and the opposite side of 17. We need to find the adjacent side (x).

Note that, at the moment, we are only dealing with this smaller triangle.

tan = opposite side / adjacent side

tan 30° = 17 / x

(√3)/3 = 17 / x

x = 17√3

Now, note that hypotenuse of the smaller triangle is the same length as the side z (adjacent and opposite side of 45° angle)

With Pythagorean theorem, we can find the hypotenuse of the smaller triangle, which equals to z.

z = √(17^2 + (17√3)^2)

z = 34

And now, finally to find y (hypotenuse of bigger triangle). We are given 45° angle and adjacent side z (34).

cos = adjacent side / hypotenuse

cos 45° = 34 / y

(√2)/2 = 34 / y

y = 34√2

14. Photo added

6 0
3 years ago
Write the expression as a product of expressions.
scoray [572]

Answer:

a^2(ab^{3}-b^{2}-c^{2})

Step-by-step explanation:

Given

a^{3}b^{3}-a^{2}b^{2}-a^{2}c^{2}

Required

Factor

a^{3}b^{3}-a^{2}b^{2}-a^{2}c^{2}

Factor out a^2

a^2(ab^{3}-b^{2}-c^{2})

<em>The expression cannot be further factored</em>

8 0
3 years ago
What is the unit rate if the candy is $7.80 for 2 pounds?
shutvik [7]

Answer:

= 3.9 candy per pound

Step-by-step explanation:

This is a fraction equal to

7.8 candy ÷ 2 pounds

We want a unit rate where

1 is in the denominator,

so we divide top and bottom by 2

7.8 candy        ÷ 2

________

2 pounds ÷ 2

=  

3.9 candy

_______

1 pound

=  

3.9 candy

_______

pound

= 3.9 candy per pound

7 0
3 years ago
If 2z=26, what does z equal?? HELP PLZ
trasher [3.6K]

Answer:

z=13

Step-by-step explanation:

Ok we are to solve for z from the given equation

2z=26

It's like making z the subject of formula

We will be able to think fast on how to make z the subject of formula from the equation

To make z the subject of formula we will have to divide both sides by 2

z=13

Therefore the value of z is 13

To solve this kind of question you must be to think on ways to eliminate the number behind the required number

Hope you understand

5 0
3 years ago
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