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3 years ago

Can someone please answer. There is one problem. There's a picture. Thank you!

Mathematics

1 answer:

schepotkina [342]3 years ago

4 0

Sin(12) ≈ 0.208

cos(x) = 0.208
  cos(x) = sin(12)
cos(78) = sin(12)

  cos(12) ≈ 0.978
  cos(68) ≈ 0.375
cos(102) ≈ -0.208
  cos(78) ≈ 0.208

The answer is D.

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A customer visiting the suit department of a certain store will purchase a suit with probability 0.22, a shirt with probability

Pachacha [2.7K]

Answer:

a. The probability that a customer purchase none of these items is 0.49

b. The probability that a customer purchase exactly 1 of these items would be of 0.28

Step-by-step explanation:

a. In order to calculate the probability that a customer purchase none of these items we would have to make the following:

let A represents suit

B represents shirt

C represents tie

P(A) = 0.22

P(B) = 0.30

P(C) = 0.28

P(A∩B) = 0.11

P(C∩B) = 0.10

P(A∩C) = 0.14

P(A∩B∩C) = 0.06

Therefore, the probability that a customer purchase none of these items we would have to calculate the following:

1 - P(A∪B∪C)

P(A∪B∪C) =P(A) + P(B) + P(C) − P(A ∩ B) − P(A ∩ C) − P(B ∩ C) + P(A ∩ B ∩ C)

= 0.22+0.28+0.30-0.11-0.10-0.14+0.06

= 0.51

Hence, 1 - P(A∪B∪C) = 1-0.51 = 0.49

The probability that a customer purchase none of these items is 0.49

b.To calculate the probability that a customer purchase exactly 1 of these items we would have to make the following calculation:

= P(A∪B∪C) - ( P(A∩B) +P(C∩B) +P(A∩C) - 2 P(A ∩ B ∩ C))

=0.51 -0.23 = 0.28

The probability that a customer purchase exactly 1 of these items would be of 0.28

6 0

3 years ago

A family paid $142.80 which included $6.80 in taxes for 4 play tickets each ticket costs the same amount how much did each perso

borishaifa [10]

$142.80-$6.80=$136 divided by 4 equals $34

8 0

3 years ago

Leah is paid semimonthly. How many fewer paychecks does she

snow_lady [41]

Answer:

Leah has 80 less paychecks than the weekly person.

Step-by-step explanation:

Leah is getting 24 paychecks in 2 years, Weekly person gets 104 paychecks in 2 years, 104 - 24 = 80 paychecks.

8 0

3 years ago

Can someone help with explain how to do these, with formulas or techniques?

Otrada [13]

I hope this helps you

6 0

3 years ago

Solve the following differential equation using using characteristic equation using Laplace Transform i. ii y" +y sin 2t, y(0) 2

kifflom [539]

Answer:

The solution of the differential equation is $y(t)= - \frac{1}{3} Sin(2t)+2 Cos(t)+\frac{5}{3} Sin(t)$

Step-by-step explanation:

The differential equation is given by: y" + y = Sin(2t)

<u>i) Using characteristic equation:</u>

The characteristic equation method assumes that y(t)= $e^{rt}$ , where "r" is a constant.

We find the solution of the homogeneus differential equation:

y" + y = 0

$y'=re^{rt}$

$y"=r^{2}e^{rt}$

$r^{2}e^{rt}+e^{rt}=0$

$(r^{2}+1)e^{rt}=0$

As $e^{rt}$ could never be zero, the term (r²+1) must be zero:

(r²+1)=0

r=±i

The solution of the homogeneus differential equation is:

$y(t)_{h}=c_{1}e^{it}+c_{2}e^{-it}$

Using Euler's formula:

$y(t)_{h}=c_{1}[Sin(t)+iCos(t)]+c_{2}[Sin(t)-iCos(t)]$

$y(t)_{h}=(c_{1}+c_{2})Sin(t)+(c_{1}-c_{2})iCos(t)$

$y(t)_{h}=C_{1}Sin(t)+C_{2}Cos(t)$

The particular solution of the differential equation is given by:

$y(t)_{p}=ASin(2t)+BCos(2t)$

$y'(t)_{p}=2ACos(2t)-2BSin(2t)$

$y''(t)_{p}=-4ASin(2t)-4BCos(2t)$

So we use these derivatives in the differential equation:

$-4ASin(2t)-4BCos(2t)+ASin(2t)+BCos(2t)=Sin(2t)$

$-3ASin(2t)-3BCos(2t)=Sin(2t)$

As there is not a term for Cos(2t), B is equal to 0.

So the value A=-1/3

The solution is the sum of the particular function and the homogeneous function:

$y(t)= - \frac{1}{3} Sin(2t) + C_{1} Sin(t) + C_{2} Cos(t)$

Using the initial conditions we can check that C1=5/3 and C2=2

<u>ii) Using Laplace Transform:</u>

To solve the differential equation we use the Laplace transformation in both members:

ℒ[y" + y]=ℒ[Sin(2t)]

ℒ[y"]+ℒ[y]=ℒ[Sin(2t)]

By using the Table of Laplace Transform we get:

ℒ[y"]=s²·ℒ[y]-s·y(0)-y'(0)=s²·Y(s) -2s-1

ℒ[y]=Y(s)

ℒ[Sin(2t)]= $\frac{2}{(s^{2}+4)}$

We replace the previous data in the equation:

s²·Y(s) -2s-1+Y(s) = $\frac{2}{(s^{2}+4)}$

(s²+1)·Y(s)-2s-1= $\frac{2}{(s^{2}+4)}$

(s²+1)·Y(s)= $\frac{2}{(s^{2}+4)}+2s+1=\frac{2+2s(s^{2}+4)+s^{2}+4}{(s^{2}+4)}$

Y(s)= $\frac{2+2s(s^{2}+4)+s^{2}+4}{(s^{2}+4)(s^{2}+1)}$

Y(s)= $\frac{2s^{3}+s^{2}+8s+6}{(s^{2}+4)(s^{2}+1)}$

Using partial franction method:

$\frac{2s^{3}+s^{2}+8s+6}{(s^{2}+4)(s^{2}+1)}=\frac{As+B}{s^{2}+4} +\frac{Cs+D}{s^{2}+1}$

2s^{3}+s^{2}+8s+6=(As+B)(s²+1)+(Cs+D)(s²+4)

2s^{3}+s^{2}+8s+6=s³(A+C)+s²(B+D)+s(A+4C)+(B+4D)

We solve the equation system:

A+C=2

B+D=1

A+4C=8

B+4D=6

The solutions are:

A=0 ; B= -2/3 ; C=2 ; D=5/3

So,

Y(s)= $\frac{-\frac{2}{3} }{s^{2}+4} +\frac{2s+\frac{5}{3} }{s^{2}+1}$

Y(s)= $-\frac{1}{3} \frac{2}{s^{2}+4} +2\frac{s }{s^{2}+1}+\frac{5}{3}\frac{1}{s^{2}+1}$

By using the inverse of the Laplace transform:

ℒ⁻¹[Y(s)]=ℒ⁻¹[ $-\frac{1}{3} \frac{2}{s^{2}+4}$ ]-ℒ⁻¹[ $2\frac{s }{s^{2}+1}$ ]+ℒ⁻¹[ $\frac{5}{3}\frac{1}{s^{2}+1}$ ]

$y(t)= - \frac{1}{3} Sin(2t)+2 Cos(t)+\frac{5}{3} Sin(t)$

3 0

3 years ago