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yKpoI14uk [10]
3 years ago
14

Write a function that models 40mg of a substance that has a half life of 84 days

Mathematics
1 answer:
lubasha [3.4K]3 years ago
5 0

Answer: The function is M(t) = 40mg*0.992^t

Step-by-step explanation:

Half life refers to the time that a given quantity to reduce to half its initial value.

This is usually a exponential decay, so we want a function of the form:

M(t) = A*r^(*t)

Were t is time, in this case, t is the number of days

A is the initial value

r is the rate of decrease, we will find that for exponential decays r must be a number between 0 and 1. If r is closer to 0, we will have a fast exponential decay, if r is closer to 1 we will have a slower exponential decay.

We have that the initial mass is 40mg, this is at t = 0.

M(0) = A*r^(0) = A = 40mg

So now we have the value of A.

Now, we know that in t = 84, the mass of the substance will be half its initial value, so it will be:

A/2 = 40mg/2 = 20mg

this means that:

M(84) = 40mg*r^(84) = 20mg

r^(84) = 20mg/40mg = 1/2

r = \sqrt[84]{1/2} = 0.992

Then the equation is:

M(t) = 40mg*0.992^t

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Mandarinka [93]

Answer:

285 min

275 min

chi

tie

Step-by-step explanation:

swim - 1.5 km

bicycle ride - 40 km

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1) Alexandra

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transition 1 time = 4 min

cycling time = distance / velocity = 40 / 15 = 2.6666667 hr = 160 min

transition 2 time = 3 min

run time = distance / velocity = 10 / 6 = 1.6666667 hr = 100 min

so total time to complete the triathlon is

= 18 + 4 +160 + 3 +100

= 285 min = 4.75 hrs

2) Chi

swim time = distance / velocity = 1.5 / 6 = 0.25 hr = 15 min

transition 1 time = 5 min

cycling time = distance / velocity = 40 / 15 = 2.6666667 hr = 160 min

transition 2 time = 5 min

run time = distance / velocity = 10 / 7.5 = 1.3333333 hr = 80 min

got flat tire that took 10 min to fix

so total time to complete the triathlon is

= 15 + 5 + 160 + 5 + 80 + 10

= 275 min

3) Alexandra won the race by 10 min

4)even though chi got flat tire , chi still won the race by 10 min,

if it took 20min to fix flat tire both their times would be 285 min and it would have been a tie.

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3 years ago
I’m confused please solve it.
Allushta [10]

Answer:

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Step-by-step explanation:

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here's the graph

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3 years ago
8<br> .<br> y = 3x - 2<br> m=<br> b=
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Answer:

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Step-by-step explanation:

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Read 2 more answers
Choose the domain for which each function is defined
klemol [59]

Answer:

Part 1) f(x)=\frac{x+4}{x} -----> x\neq 0

Part 2) f(x)=\frac{x}{x+4} ----> x\neq -4

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Step-by-step explanation:

we know that

The domain of a function is the set of all possible values of x

Part 1) we have

f(x)=\frac{x+4}{x}

we know that

In a quotient the denominator cannot be equal to zero

so

For the value of x=0 the function is not defined

therefore

The domain is

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Part 2) we have

f(x)=\frac{x}{x+4}

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In a quotient the denominator cannot be equal to zero

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Part 3) we have

f(x)=x(x+4)

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Part 4) we have

f(x)=\frac{4}{x^2+8x+16}

we know that

In a quotient the denominator cannot be equal to zero

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Equate the denominator to zero

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Remember that

x^2+8x+16=(x+4)^2

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The solution is x=-4

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For the value of x=-4 the function is not defined

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