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Tresset [83]
3 years ago
11

Use​ DeMoivre's Theorem to find the indicated power of the complex number. Write the answer in rectangular form.

Mathematics
1 answer:
slava [35]3 years ago
3 0

Answer:

After solving the power:

\bold{2(cos60^\circ+isin60^\circ)}

Rectangular form:

\bold{1+i\sqrt3}

Step-by-step explanation:

Given the complex number:

2(cos20^\circ+isin20^\circ)^3

To find:

The indicated power by using De Moivre's theorem.

The complex number in rectangular form.

Rectangular form of a complex number is given as a+ib where a and b are real numbers.

Solution:

First of all, let us have a look at the De Moivre's theorem:

(cos\theta+isin\theta )^n=cos(n\theta)+isin(n\theta )

First of all, let us solve:

(cos20^\circ+isin20^\circ)^3

Let us apply the De Moivre's Theorem:

Here, n = 3

(cos20^\circ+isin20^\circ)^3 = cos(3 \times 20)^\circ+isin(3 \times 20)^\circ\\\Rightarrow cos60^\circ+isin60^\circ

Now, the given complex number becomes:

2(cos60^\circ+isin60^\circ)

Let us put the values of cos60^\circ = \frac{1}{2} and sin60^\circ = \frac{\sqrt3}{2}

2(\dfrac{1}{2}+i\dfrac{\sqrt3}2)\\\Rightarrow (2 \times \dfrac{1}{2}+i\dfrac{\sqrt3}2\times 2)\\\Rightarrow \bold{1 +i\sqrt3 }

So, the rectangular form of the given complex number is:

\bold{1+i\sqrt3}

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Oksana_A [137]

Answer:

(a) E(X) = 950

(b) $ COV = 0.007255$

(c) P(X > 980) = 0.00001\\\\

Step-by-step explanation:

The given problem can be solved using binomial distribution since the product either fails or passes, the probability of failure or success is fixed and there are n repeated trials.

probability of failure = q = 0.05

probability of success = p = 1 - 0.05 = 0.95

number of trials = n = 1000

(a) What is the expected number of non-defective units?

The expected number of non-defective units is given by

E(X) = n \times p \\\\E(X) = 1000 \times 0.95 \\\\E(X) = 950

(b) what is the COV of the number of non-defective units?

The coefficient of variance is given by

$ COV = \frac{\sigma}{E(X)} $

Where the standard deviation is given by

\sigma = \sqrt{n \times p\times q} \\\\\sigma = \sqrt{1000 \times 0.95\times 0.05} \\\\\sigma = 6.892

So the coefficient of variance is

$ COV = \frac{6.892}{950} $

$ COV = 0.007255$

(c) What is the probability of having more than 980 non-defective units?

We can use the Normal distribution as an approximation to the Binomial distribution since n is quite large and so is p.

P(X > 980) = 1 - P(X < 980)\\\\P(X > 980) = 1 - P(Z < \frac{x - \mu}{\sigma} )\\\\

We need to consider the continuity correction factor whenever we use continuous probability distribution (Normal distribution) to approximate discrete probability distribution (Binomial distribution).

P(X > 980)  = 1 - P(Z < \frac{979.5 - 950}{6.892} )\\\\P(X > 980)  = 1 - P(Z < \frac{29.5}{6.892} )\\\\P(X > 980)  = 1 - P(Z < 4.28)\\\\

The z-score corresponding to 4.28 is 0.99999

P(X > 980) = 1 - 0.99999\\\\P(X > 980) = 0.00001\\\\

So it means that it is very unlikely that there will be more than 980 non-defective units.

8 0
3 years ago
732,178+167-542,137=
madreJ [45]
( 732,178 + 167 ) = 899,178
899,178 - 542,137 = *357,041 that's the last result.
3 0
3 years ago
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17/100 in simplest form
sveticcg [70]
17 is a prime number so the simplest form is 17/100
5 0
3 years ago
HELP PLZZ ANWSER I KNOW​
marishachu [46]

Answer:

2(w+10)=50

Step-by-step explanation:

rectangle two sides are equal and the other two sides are equal

so we know two sides are ten in this equation the w can be the unknown sides so 2*w and 2*10 = 50

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2 years ago
Express 900 as a product of its prime factors im index form ​
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Step-by-step explanation: Divide by successive primes:

900 / 2 = 450

450 / 2 = 225

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Write down the prime factors:

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Write them in index form:

2² × 3² × 5²

3 0
3 years ago
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