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Vedmedyk [2.9K]
2 years ago
8

A Cepheid star is a type of variable star, which means its brightness is not constant. The relationship between the brightness o

f a Cepheid star and its period, or length of its pulse, is given by M = –2.78(log P) – 1.35, where M is the absolute magnitude, or brightness, of the star, and P is the number of days required for the star to complete one cycle. What is the absolute magnitude of a star that has a period of 45 days? Use a calculator. Round your answer to the nearest hundredth. –5.95 –4.60 3.25 4.60
Mathematics
2 answers:
White raven [17]2 years ago
8 0

Answer:

The absolute brightness of the Cepheid star after a period of 45 days is -5.95

Step-by-step explanation:

Since the absolute magnitude or brightness of a Cepheid star is related to its period or length of its pulse by

M = –2.78(log P) – 1.35 where M = absolute magnitude and P = period or length of pulse.

From our question, it is given that P = 45 days.

So, M = –2.78(log P) – 1.35

M = –2.78(log 45) – 1.35

M = –2.78(1.6532) – 1.35

M = -4.60 - 1.35

M = -5.95

So, the absolute magnitude or brightness M of a Cepheid star after a period P of 45 days is -5.95

BaLLatris [955]2 years ago
7 0

Answer:

A

Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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1 year ago
Let T W Rn ! Rm be a linear transformation. Show that if T maps two linearly independent vectors onto a linearly dependent set,
Mandarinka [93]

Answer:

The solution proves that the equation has a non-trivial solution.  

Step-by-step explanation:

We want to show that the equation has nontrivial solutions for which c_{1} T(v_{1} ) + c_{2} T(v_{2} ) + c_{3} T(v_{3}) = 0

Let c_{i} be a set of non-zero numbers such that that c_{1} v_{1}  + c_{2} v_{2} + c_{3} v_{3}  = 0

Because T is a linear solution:

c_{1}T(v_{1} ) + c_{2} T (v_{2} ) + c_{3} T (v_{3} ) = T (c_{1} v_{1} ) + T(c_{2}v_{2} ) + T(c_{3} v_{3} )

                                            = T(c_{1}v_{1}  + c_{2} v_{2}  + c_{3} v_{3} )

                                            = T(0)

                                            = T (00)

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6 0
2 years ago
The time between arrivals of small aircraft at a county airport is exponentially distributed with a mean of one hour. Round the
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Answer:

a) 0.019

b) 0.563

c) x = 1.966 hours

Step-by-step explanation:

E(X) = 1

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The cumulative distribution function is given as

P(X ≤ x) = 1 - e^(-λ.x)

a) The time between the arrivals of small aircraft at a county airport that is exponentially distributed.

But the number of planes that land every hour will be obtained using the Poisson distribution formula.

It is the best for discrete systems.

Poisson distribution formula is given as

P(X = x) = (e^-λ)(λˣ)/x!

λ = 1 aircraft per hour.

The probability that more than three aircraft arrive within an hour = P(X > 3)

P(X > 3) = 1 - P(X ≤ 3) = 1 - [P(X=0) + P(X=1) + P(X=2) + P(X=3)]

P(X > 3) = 1 - 0.98101 = 0.01899 = 0.019 to 3 d.p

b) If 30 separate one-hour intervals are chosen, what Is the probability that no interval contains more than three arrivals

Probability of one 1-hour interval not containing more than 3 arrivals = 1 - P(X > 3)

= 1 - 0.01899 = 0.98101

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c) Determine the length of an interval of time (In hours) such that the probability that no arrivals occur during the interval is 0.14

We can now use the cumulative distribution function for exponential random variable for this

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P(X > x) = e^(-λ.x)

λ = 1, x = ?,

0.14 = e⁻ˣ

e⁻ˣ = 0.14

In e⁻ˣ = In 0.14 = -1.966

-x = -1.966

x = 1.966 hours

Hope this Helps!!!

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Answer:

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Answer:

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Step-by-step explanation:

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We get:

\frac{ 40!}{10!*10!*10!*10!} = 4.7*10^{21}

Part 2:

The number of ways in which we can choose k element for a group of n elements and the order in which they are chose matters is calculate with permutation as:

nPk = \frac{ n!}{(n-k)!}

So in this case there are 4 offices in the research board, those are director,  assistant director, quality control analyst and correspondent. Additionally this 4 offices are going to choose from a group of 5 doctors.

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We get:

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7 0
1 year ago
Read 2 more answers
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