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3 years ago

I need help with 21 and 22. please.

Mathematics

1 answer:

guajiro [1.7K]3 years ago

6 0

21. A

22. G

I Am writing this part because it said that the answer didnt have enough characters so just ignore this

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1. Billy's mother started a college fund on Billy's 8th birthday. She

MaRussiya [10]

When billy turns 18 he will have $3,099.6 in his account because .021 percent x $8,200= $172.20 per year x 18 years = $3,099.60

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3 years ago

What is 500 divided by 6.7

pishuonlain [190]

$\boxed{ \frac{500}{6.7} = 74.627\ Answer}$

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3 years ago

Consider the initial value problem y′+5y=⎧⎩⎨⎪⎪0110 if 0≤t<3 if 3≤t<5 if 5≤t<[infinity],y(0)=4. y′+5y={0 if 0≤t<311 i

rosijanka [135]

It looks like the ODE is

$y'+5y=\begin{cases}0&\text{for }0\le t$

with the initial condition of $y(0)=4$ .

Rewrite the right side in terms of the unit step function,

$u(t-c)=\begin{cases}1&\text{for }t\ge c\\0&\text{for }t$

In this case, we have

$\begin{cases}0&\text{for }0\le t$

The Laplace transform of the step function is easy to compute:

$\displaystyle\int_0^\infty u(t-c)e^{-st}\,\mathrm dt=\int_c^\infty e^{-st}\,\mathrm dt=\frac{e^{-cs}}s$

So, taking the Laplace transform of both sides of the ODE, we get

$sY(s)-y(0)+5Y(s)=\dfrac{e^{-3s}-e^{-5s}}s$

Solve for $Y(s)$ :

$(s+5)Y(s)-4=\dfrac{e^{-3s}-e^{-5s}}s\implies Y(s)=\dfrac{e^{-3s}-e^{-5s}}{s(s+5)}+\dfrac4{s+5}$

We can split the first term into partial fractions:

$\dfrac1{s(s+5)}=\dfrac as+\dfrac b{s+5}\implies1=a(s+5)+bs$

If $s=0$ , then $1=5a\implies a=\frac15$ .

If $s=-5$ , then $1=-5b\implies b=-\frac15$ .

$\implies Y(s)=\dfrac{e^{-3s}-e^{-5s}}5\left(\frac1s-\frac1{s+5}\right)+\dfrac4{s+5}$

$\implies Y(s)=\dfrac15\left(\dfrac{e^{-3s}}s-\dfrac{e^{-3s}}{s+5}-\dfrac{e^{-5s}}s+\dfrac{e^{-5s}}{s+5}\right)+\dfrac4{s+5}$

Take the inverse transform of both sides, recalling that

$Y(s)=e^{-cs}F(s)\implies y(t)=u(t-c)f(t-c)$

where $F(s)$ is the Laplace transform of the function $f(t)$ . We have

$F(s)=\dfrac1s\implies f(t)=1$

$F(s)=\dfrac1{s+5}\implies f(t)=e^{-5t}$

We then end up with

$y(t)=\dfrac{u(t-3)(1-e^{-5t})-u(t-5)(1-e^{-5t})}5+5e^{-5t}$

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3 years ago

How many meters are in 2.5 kilometers?

Ulleksa [173]

Answer:2500

Step-by-step explanation:

no cap

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3 years ago

Read 2 more answers

Use the table to predict the number of times you will spin 3 when you spin the spinner 100 times. Spinning a Spinner Number spun

Naily [24]

Step-by-step explanation:

I am not sure i understand the text you put there.

what I think is clear is to find the expected number of the appearances of the number 3 when spinning the spinner 100 times.

to do this we start by checking the given information.

and we see that the given table based on the result of in total 50 spins (7+8+9+7+11+8).

when spinning the spinner additional times, we can expect the same structure of distribution of the individual possible results as before. we just scale everything to the new size of the overall sample.

before, with 50 spins, we saw the number 3 9 times.

so, with 100 spins, which is 2×50, we expect to see the number 3 then 2×9 = 18 times.

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2 years ago