We are choosing 2
2
r
shoes. How many ways are there to avoid a pair? The pairs represented in our sample can be chosen in (2)
(
n
2
r
)
ways. From each chosen pair, we can choose the left shoe or the right shoe. There are 22
2
2
r
ways to do this. So of the (22)
(
2
n
2
r
)
equally likely ways to choose 2
2
r
shoes, (2)22
(
n
2
r
)
2
2
r
are "favourable."
Another way: A perhaps more natural way to attack the problem is to imagine choosing the shoes one at a time. The probability that the second shoe chosen does not match the first is 2−22−1
2
n
−
2
2
n
−
1
. Given that this has happened, the probability the next shoe does not match either of the first two is 2−42−2
2
n
−
4
2
n
−
2
. Given that there is no match so far, the probability the next shoe does not match any of the first three is 2−62−3
2
n
−
6
2
n
−
3
. Continue. We get a product, which looks a little nicer if we start it with the term 22
2
n
2
n
. So an answer is
22⋅2−22−1⋅2−42−2⋅2−62−3⋯2−4+22−2+1.
2
n
2
n
⋅
2
n
−
2
2
n
−
1
⋅
2
n
−
4
2
n
−
2
⋅
2
n
−
6
2
n
−
3
⋯
2
n
−
4
r
+
2
2
n
−
2
r
+
1
.
This can be expressed more compactly in various ways.
Its C cause the y intercept is -5
To convert 8.0464x10^-7 from scientific notation to decimal notation, you need to move the decimal point to the left seven times.
Therefore the answer is:
0.00000080464
Note: 10^-7 equals 1/10^7
8.0464x10^-7 can be rewritten as:
8.0464/10^7 (i.e. divide 8.0464 by 10000000)
which results: 0.00000080464
The angle of depression from the aeroplane to the ground will be 30 degrees.
<h3>What is trigonometry?</h3>
Trigonometry is the branch of mathematics which set up a relationship between the sides and angle of the right-angle triangles.
Given that:-
- An aeroplane is flying at the height of 10 km above the ground the distance along the ground from the aeroplane to the airport is 10√3 km
The angle of depression will be calculated as the angle between the horizontal and the height of the plane as shown in the figure below.
As we know that the perpendicular theta is height and the base ratio is angle tan theta.
tanФ = Height / Base
tanФ = 10 / 10 √3
tanФ = 1 / √3
Ф = tan⁻¹( 1 / √3 ) = 30°
Therefore the angle of depression from the aeroplane to the ground will be 30 degrees.
To know more about Trigonometry follow
brainly.com/question/24349828
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