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3 years ago

Is -9.1234567... rational or irrational?

Mathematics

2 answers:

Sholpan [36]3 years ago

6 0

It is irrational
all decimals or fractions are irrational

Masteriza [31]3 years ago

5 0

Answer:

That number is irrational because no matter what, any decimals or fractions are going to be irrational.

You might be interested in

A car manufacturer builds trucks and cars both in red, blue, and green colors. Let B represent the set of all red vehicles produ

telo118 [61]

Answer:

Step-by-step explanation:

The universal set, U is a set of all vehicles produced by the manufacturer.

U = red, blue and green vehicles(both cars and trucks)

B = all red vehicles produced by the manufacturer(both cars and trucks)

C = red, blue and green trucks

C ' = all elements that are not in C but are in the universal set

C ' = red, blue and green cars

B intersection C ' = all elements that are common to set B and set C '. Therefore,

B intersection C ' = red cars

5 0

3 years ago

A survey on British Social Attitudes asked respondents if they had ever boycotted goods for ethical reasons (Statesman, January

Blababa [14]

Answer:

a) 27.89% probability that two have ever boycotted goods for ethical reasons

b) 41.81% probability that at least two respondents have boycotted goods for ethical reasons

c) 41.16% probability that between 3 and 6 have boycotted goods for ethical reasons

d) The expected number is 2.3 and the standard deviation is 1.33.

Step-by-step explanation:

We use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

23% of the respondents have boycotted goods for ethical reasons.

This means that $p = 0.23$

a) In a sample of six British citizens, what is the probability that two have ever boycotted goods for ethical reasons?

This is P(X = 2) when n = 6. So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 2) = C_{6,2}.(0.23)^{2}.(0.77)^{4} = 0.2789$

27.89% probability that two have ever boycotted goods for ethical reasons

b) In a sample of six British citizens, what is the probability that at least two respondents have boycotted goods for ethical reasons?

Either less than two have, or at least two. The sum of the probabilities of these events is decimal 1. So

$P(X < 2) + P(X \geq 2) = 1$

$P(X \geq 2) = 1 - P(X < 2)$

In which

$P(X < 2) = P(X = 0) + P(X = 1)$

$P(X = 0) = C_{6,0}.(0.23)^{0}.(0.77)^{6} = 0.2084$

$P(X = 1) = C_{6,1}.(0.23)^{1}.(0.77)^{5} = 0.3735$

$P(X < 2) = P(X = 0) + P(X = 1) = 0.2084 + 0.3735 = 0.5819$

$P(X \geq 2) = 1 - P(X < 2) = 1 - 0.5819 = 0.4181$

41.81% probability that at least two respondents have boycotted goods for ethical reasons

c) In a sample of ten British citizens, what is the probability that between 3 and 6 have boycotted goods for ethical reasons?

Now n = 10.

$P(3 \leq X \leq 6) = P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6)$

$P(X = 3) = C_{10,3}.(0.23)^{3}.(0.77)^{7} = 0.2343$

$P(X = 4) = C_{10,4}.(0.23)^{4}.(0.77)^{6} = 0.1225$

$P(X = 5) = C_{10,5}.(0.23)^{5}.(0.77)^{5} = 0.0439$

$P(X = 6) = C_{10,6}.(0.23)^{6}.(0.77)^{4} = 0.0109$

$P(3 \leq X \leq 6) = P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) = 0.2343 + 0.1225 + 0.0439 + 0.0109 = 0.4116$

41.16% probability that between 3 and 6 have boycotted goods for ethical reasons

d) In a sample of ten British citizens, what is the expected number of people that have boycotted goods for ethical reasons? Also find the standard deviation.

$E(X) = np = 10*0.23 = 2.3$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{10*0.23*0.77} = 1.33$

The expected number is 2.3 and the standard deviation is 1.33.

5 0

3 years ago

The diameter of a circle is 2 units. What is the radius of the circle

Luda [366]

Answer:

Step-by-step explanation:

The radius is half the size of the diameter.

2 / 2 = 1

3 0

3 years ago

The diameter of a quarter is 24.26 mm. Find the area

Vinil7 [7]

R=12.13
A=pi×r²
A=pi×12.13²
A≈462.2442041
A≈462.2 (to the nearest tenth).

So the answer is A≈462.2.

6 0

4 years ago

Find the values of which satisfy the equation. 2 cos (2B+30°) = -√3 in the domain OP ≤B≤360°

PSYCHO15rus [73]

Answer:

60 and 90

Step-by-step explanation:

$2 \cos(2 \beta + 30) = - \sqrt{3}$

$\cos(2 \beta + 30) = - \frac{ \sqrt{3} }{2}$

$2 \beta + 30 = \cos {}^{ - 1} ( \frac{ - \sqrt{3} }{2} )$

First solution.

$2 \beta + 30 = 150$

$2 \beta = 120$

$\beta = 60$

Second solution

$2 \beta + 30 = 210$

$2 \beta = 180$

$\beta = 90$

5 0

2 years ago