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3 years ago

General solution of equation sin x + sin 5x = sin 2x + sin 4x is

Mathematics

1 answer:

zaharov [31]3 years ago

7 0

Answer:

x=nπ3, n∈I

Step-by-step explanation:

sin x + sin 5x = sin 2x + sin 4x

⇒⇒ 2 sin 3x cos 2x = 2 sin 3x cos x

⇒⇒ 2 sin 3x(cos 2x - cos x) = 0

⇒ sin 3x=0 ⇒ 3x=nπ ⇒ x=nπ3⇒ sin 3x=0 ⇒ 3x=nπ ⇒ x=nπ3 , n∈I, n∈I

or cos 2x−cos x=0 ⇒ cos 2x=cos xcos 2x-cos x=0 ⇒ cos 2x=cos x

⇒ 2x=2nπ±x ⇒ x=2nπ, 2nπ3⇒ 2x=2nπ±x ⇒ x=2nπ, 2nπ3 , n∈I, n∈I

But solutions obtained by x=2nπx=2nπ , n∈I, n∈I or x=2nπ3x=2nπ3 , n∈I, n∈I are all involved in x=nπ3x=nπ3 , n∈I

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36 2/5 x what = 109 1/5

tamaranim1 [39]

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3 years ago

Read 2 more answers

Bo and Brica are yoga instructors. Between the both of them, they teach 46 yoga classes each week. If Brica teaches 11 fewer tha

PtichkaEL [24]

Bo teaches 19 classes and Brica teaches 27 classes per week

Step-by-step explanation:

Bo and Brica are yoga instructors

They teach 46 yoga classes each week
Brica teaches 11 fewer than twice as many as Bo

We need to find how many classes each instructor teaches per week

Assume that Bo teaches x classes per week

∵ Bo teaches x classes per week

∵ Brica teaches 11 fewer than twice as many as Bo

∵ Twice means times 2 and 11 fewer is - 11

- Multiply x by 2 and subtract 11 from the product

∴ Brica teaches 2x - 11 classes per week

∵ They teach 46 classes per week

- Add the number of their classes and equate the sum by 46

∴ x + 2x - 11 = 46

- Add the like terms in the left hand side

∴ 3x - 11 = 46

- Add 11 to both sides

∴ 3x = 57

- Divide both sides by 3

∴ x = 19

∵ Bo teaches x classes per week

∴ Bo teaches 19 classes per week

∵ Brica teaches 2x - 11 classes per week

∴ Brica teaches 2(19) - 11 = 27 classes per week

Bo teaches 19 classes and Brica teaches 27 classes per week

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3 years ago

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natta225 [31]

Answer:

a) 99% of the sample means will fall between 0.933 and 0.941.

b) By the Central Limit Theorem, approximately normal, with mean 0.937 and standard deviation 0.0015.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

(a) If the true mean is 0.9370 with a standard deviation of 0.0090 within what interval will 99% of the sample means fail?

Samples of 34 means that $n = 34$

We have that $\mu = 0.937, \sigma = 0.009$

By the Central Limit Theorem, $s = \frac{0.009}{\sqrt{34}} = 0.0015$

Within what interval will 99% of the sample means fail?

Between the (100-99)/2 = 0.5th percentile and the (100+99)/2 = 99.5th percentile.

0.5th percentile:

X when Z has a pvalue of 0.005. So X when Z = -2.575.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$-2.575 = \frac{X - 0.937}{0.0015}$

$X - 0.937 = -2.575*0.0015$

$X = 0.933$

99.5th percentile:

X when Z has a pvalue of 0.995. So X when Z = 2.575.

$Z = \frac{X - \mu}{s}$

$2.575 = \frac{X - 0.937}{0.0015}$

$X - 0.937 = 2.575*0.0015$

$X = 0.941$

99% of the sample means will fall between 0.933 and 0.941.

(b) If the true mean 0.9370 with a standard deviation of 0.0090, what is the sampling distribution of ¯X?

By the Central Limit Theorem, approximately normal, with mean 0.937 and standard deviation 0.0015.

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Answer:

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

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