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shepuryov [24]
3 years ago
9

I know you have to use the half life formula but I don’t know how to use it could someone show how to find the solution step by

step? Thank you

Mathematics
1 answer:
n200080 [17]3 years ago
7 0

Answer:

A = Pe ^{-0.03108 * t}

Step-by-step explanation:

Note: these are typically two part questions...

you have the model and have to FIRST find a constant value "k"

once you have the "k" value you plug that into the model to finish the problem

A = Pe ^{-kt} is a typical version of the continuous decay...

e is "e 2.717" not a variable "e"

so... step 1.. fink k

you are told that the 1/2 life is 22.3 years...

so lets assume that we started with 2 units of lead, and waited for it to decrease to 1 (1 is 1/2 of 2)

you would have

1 = 2e^{k * 22.3}

.5 = e^{k * 22.3}

ln(.5) = 22.3k ln(e)

ln(e) = 1

ln(.5) = 22.3k

ln(.5) = 22.3k ln(e)

\frac{ln(.5) }{22.3} = k

\frac{\ln \left(0.5\right)}{22.3}=-0.03108 = k

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Which numbers represent the measure of the sides of a right triangle?
Dominik [7]

Answer:

2.8, 4.5, 5.3

numbers represent the measure of the sides of a right triangle.

2.8²+4.5²=5.3²

7.84+20.25=28.09

28.09=28.09

8 0
3 years ago
You are riding a roller coaster when a shoe falls off your foot. The function y=300−16t2 represents the height y (in feet) of th
Juli2301 [7.4K]

Answer:

Time to land on 11ft is 4.25 seconds

Step-by-step explanation:

Given

y = 300 - 16t^2

Required

Solve for t when height is 11ft

This implies that y = 11

So: substitute 11 for y in y = 300 - 16t^2

11 = 300 - 16t^2

Collect Like Terms

16t^2 = 300 - 11

16t^2 = 289

Express both sides as squares

4^2 * t^2 = 17^2

(4t)^2 = 17^2

Take square roots of both sides (ignore negative)

4t = 17

Solve for t

t = \frac{17}{4}

t = 4.25

Hence, time to land on 11ft is 4.25 seconds

8 0
3 years ago
A number is chosen at random from 1 to 50. find the probability of selecting numbers with 3 in the tens places
andrew-mc [135]
5/50 =.1 or 10% or 1/10
3 0
3 years ago
A random sample of 49 measurements from one population had a sample mean of 15, with sample standard deviation 5. An independent
kotykmax [81]

Answer:

Comparing the p value with the significance level \alpha=0.01 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, and the difference between the two groups is significantly different.  

Step-by-step explanation:

\bar X_{1}=15 represent the mean for sample 1

\bar X_{2}=18 represent the mean for sample 2

s_{1}=5 represent the sample standard deviation for 1  

s_{f}=6 represent the sample standard deviation for 2  

n_{1}=49 sample size for the group 2  

n_{2}=64 sample size for the group 2  

\alpha=0.01 Significance level provided

t would represent the statistic (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to check if the difference in the population means, the system of hypothesis would be:  

Null hypothesis:\mu_{1}-\mu_{2}=0  

Alternative hypothesis:\mu_{1} - \mu_{2}\neq 0  

We don't have the population standard deviation's, so for this case is better apply a t test to compare means, and the statistic is given by:  

t=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}} (1)

And the degrees of freedom are given by df=n_1 +n_2 -2=49+64-2=111  

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

With the info given we can replace in formula (1) like this:  

t=\frac{(15-18)-0}{\sqrt{\frac{5^2}{49}+\frac{6^2}{64}}}}=-2.897

P value

Since is a bilateral test the p value would be:  

p_v =2*P(t_{111}  

Comparing the p value with the significance level \alpha=0.01 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, and the difference between the two groups is significantly different.  

7 0
3 years ago
What are all the values of x that make the quadratic A<br> equation below true?<br> x² – 16=0
Rudiy27
X^2 = 16
x = 4
x = -4
good luck :)
8 0
3 years ago
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