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Monica [59]
3 years ago
10

Find the probability that when a couple has three children, at least one of themis a girl. (Assume that boys and girls are equal

ly likely.)
Mathematics
1 answer:
kvv77 [185]3 years ago
6 0

Answer:   \bold{\dfrac{7}{8}=87.5\%}

<u>Step-by-step explanation:</u>

"At least one girl" means P(1 girl) + P(2 girls) + P(3 girls)   or   1 - P(all boys)

I will use the latter: 1 - P(all boys)

P(all boys) = \dfrac{1}{2}\times \dfrac{1}{2}\times \dfrac{1}{2}=\dfrac{1}{8}

1 - P(all\ boys) \quad = \quad 1-\dfrac{1}{8}\quad =\large\boxed{\dfrac{7}{8}}

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Convert from rectangular to polar coordinates:Note: Choose r and θ such that r is non-negative and 0 ≤ θ &lt; 2πa. (6,0)b. (9,9/
Anuta_ua [19.1K]

Answer:

The polar coordinates are as follow:

a. (6,2π)

b. (18, π/3)

c. (2√2 , 3π/4)

d. (2, 5π /6)

Step-by-step explanation:

To convert the rectangular coordinates into polar coordinates, we need to calculate r, θ .

To calculate r, we use Pythagorean theorem:

r = \sqrt{ x^{2} +y^{2} } ---- (1)

To calculate the θ, first we will find out the θ '  using the inverse of cosine as it is easy to calculate.

So,    θ '  = cos ⁻¹  (x/r)

If  y  ≥  0  then  θ  =  ∅

If  y  <  0  then  θ  =  2 π  −  ∅

For a. (6,0)

Sol:

Using the formula in equation (1). we get the value of r as:

r = \sqrt{6^{2} + 0^{2}  }

r = 6

And ∅  = cos ⁻¹  (x/r)

∅ = cos ⁻¹  (6/6)

∅  =cos ⁻¹   (1) = 2π

As If  y  ≥  0  then  θ  =  ∅

So ∅ = 2π

The polar coordinates are (6,2π)

For a. (9,9/\sqrt{3})

Sol:

r = 9 + 3(3) = 18

and ∅  = cos ⁻¹  (x/r)

∅ = cos ⁻¹  (9/18)

∅ = cos ⁻¹   (1/2) = π/3

As  If  y  ≥  0  then  θ  =  ∅

then θ  = π/3

The polar coordinates are (18, π/3)

For (-2,2)

Sol:

r =√( (-2)²+(2)² )

r = 2 √2

and ∅  = cos ⁻¹  (x/r)

∅ = cos ⁻¹  (-2/ 2 √2)

∅ = 3π/4

As  If  y  ≥  0  then  θ  =  ∅

then   θ  = 3π/4

The polar coordinates are (2√2 , 3π/4)

For (-√3, 1)

Sol:

r = √ ((-√3)² + 1²)

r = 2

and ∅  = cos ⁻¹  (x/r)

∅  = cos ⁻¹ ( -√3/2)

∅  = 5π /6

As  If  y  ≥  0  then  θ  =  ∅

So  θ  = 5π /6

The polar coordinates are (2, 5π /6)

6 0
3 years ago
Which complex number has a distance of V17 from the origin on the complex plane?
Nataly_w [17]

Answer:

4-i

Step-by-step explanation:

Use the formula for the distance of a complex number from the origin on the complex plane.

\sqrt{a^2+b^2}

a+bi

4-i

\sqrt{4^2-i^2}

\sqrt{4^2+(-1)^2}=\sqrt{16+1}=\sqrt{17}

The complex number that has a distance of \sqrt{17} is 4-i.

5 0
4 years ago
Please help, and stop sending me links
otez555 [7]

Answer:

I need this answer as well

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
Use the frequency table below to determine how many students received a score of 70 or better on an English exam.
storchak [24]

Answer:

15

Step-by-step explanation:

From the frequency table

70 - 79 → 5

80 - 89 → 6

90 - 100 → 4

Students scoring 70 or better = 5 + 6 + 4 = 15

6 0
3 years ago
How many units of meters make a kilometer?
Delicious77 [7]
ANSWER: 1000m


EXPLANATION: 1 km = 1000
3 0
3 years ago
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