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xxMikexx [17]
3 years ago
14

If cos=20/29 and it is in the 4th quadrant, what is tan2x?

Mathematics
1 answer:
Harrizon [31]3 years ago
4 0
Think it's done like this but im not sure if the tan2x part is correct

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Our faucet is broken, and a plumber has been called. The arrival time of the plumber is uniformly distributed between 1pm and 7p
Ymorist [56]

Answer:

E(A+B) = E(A)+E(B)=4+0.5 =4.5 hours

Var(A+B)= Var(A)+Var(B)=3+0.25 hours^2=3.25 hours^2

Step-by-step explanation:

Let A the random variable that represent "The arrival time of the plumber ". And we know that the distribution of A is given by:

A\sim Uniform(1 ,7)

And let B the random variable that represent "The time required to fix the broken faucet". And we know the distribution of B, given by:

B\sim Exp(\lambda=\frac{1}{30 min})

Supposing that the two times are independent, find the expected value and the variance of the time at which the plumber completes the project.

So we are interested on the expected value of A+B, like this

E(A +B)

Since the two random variables are assumed independent, then we have this

E(A+B) = E(A)+E(B)

So we can find the individual expected values for each distribution and then we can add it.

For ths uniform distribution the expected value is given by E(X) =\frac{a+b}{2} where X is the random variable, and a,b represent the limits for the distribution. If we apply this for our case we got:

E(A)=\frac{1+7}{2}=4 hours

The expected value for the exponential distirbution is given by :

E(X)= \int_{0}^\infty x \lambda e^{-\lambda x} dx

If we use the substitution y=\lambda x we have this:

E(X)=\frac{1}{\lambda} \int_{0}^\infty y e^{-\lambda y} dy =\frac{1}{\lambda}

Where X represent the random variable and \lambda the parameter. If we apply this formula to our case we got:

E(B) =\frac{1}{\lambda}=\frac{1}{\frac{1}{30}}=30min

We can convert this into hours and we got E(B) =0.5 hours, and then we can find:

E(A+B) = E(A)+E(B)=4+0.5 =4.5 hours

And in order to find the variance for the random variable A+B we can find the individual variances:

Var(A)= \frac{(b-a)^2}{12}=\frac{(7-1)^2}{12}=3 hours^2

Var(B) =\frac{1}{\lambda^2}=\frac{1}{(\frac{1}{30})^2}=900 min^2 x\frac{1hr^2}{3600 min^2}=0.25 hours^2

We have the following property:

Var(X+Y)= Var(X)+Var(Y) +2 Cov(X,Y)

Since we have independnet variable the Cov(A,B)=0, so then:

Var(A+B)= Var(A)+Var(B)=3+0.25 hours^2=3.25 hours^2

3 0
3 years ago
Is there anybody taking the algebra test in texas i would really appreciate the answeres​
s344n2d4d5 [400]

Answer:

which one, i just took a test, and im from texas

Step-by-step explanation:

6 0
2 years ago
A company loses $780 as a result of shipping delay. The 6 owners of the company must share the loss equally. Write an expression
Stels [109]
C that’s the answer very easy there u go
3 0
3 years ago
Find the value of 17<br> 33 rounded to the nearest ten-thousandth.
alexira [117]

Answer:

0.5152

Step-by-step explanation:

7 0
3 years ago
A rectangular one story house covers an area of 3,700 square feet. The ceilings are 8 feet high. What is the volume of the inter
notsponge [240]

Answer:

43100 cubic feet

Step-by-step explanation:

Floor 1: 3700 * 8 = 29600

Floor 2: 50 * 30 * 9 = 13600

Total = 29600+13600=43100

8 0
3 years ago
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