Answer
Cluster sampling. See explanation below.
Step-by-step explanation:
For this case they not use random sampling since we are selecting people from flights. Because we select just 5 random flights.
Is not stratified sampling since we don't have strata clearly defined on this case, and other important thing is that in order to apply this method we need homogeneous strata groups and that's not satisfied on this case.
Is not convenience sampling because they NOT use a non probability method in order to select the people from the flights.
So then the only possible method is cluster sampling since we have clusters clearly defined (Passengers from the airlines), and we satisfy the condition of homogeneous characteristics on the clusters and an equal chance of being a part of the sample, since we are selecting RANDOMLY, the 5 flights to take the information.
Answer: 16 1/2
Step-by-step explanation:
It's easiest to multiply improper fractions and then to convert them back into mixed numbers, so 4 1/2 would become 9/2 and 3 2/3 would become 11/3. 
= 99/6. Now just simplify to 33/2 and then convert back into a mixed number. 16 1/2
Plug in (7, 12) for x and y in the equation.
12 = 2(7) + 1
12 = 14 + 1
12 ≠ 15
Therefore, (7, 12) is not on the straight line equation.
<u>Answer:</u>
x = ±5
<u>Step-by-step explanation:</u>
We are given the following polynomial function and we are to find all of its real roots:
Let 
so we can now write it as:
Factorizing it to get:
Substitute back to get:
The quadratic factor has only complex roots. Therefore, the real roots are x = ±5.
(tan²(<em>θ</em>) cos²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>))
Recall that
tan(<em>θ</em>) = sin(<em>θ</em>) / cos(<em>θ</em>)
so cos²(<em>θ</em>) cancels with the cos²(<em>θ</em>) in the tan²(<em>θ</em>) term:
(sin²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>))
Recall the double angle identity for cosine,
cos(2<em>θ</em>) = 2 cos²(<em>θ</em>) - 1
so the 1 in the denominator also vanishes:
(sin²(<em>θ</em>) - 1) / (2 cos²(<em>θ</em>))
Recall the Pythagorean identity,
cos²(<em>θ</em>) + sin²(<em>θ</em>) = 1
which means
sin²(<em>θ</em>) - 1 = -cos²(<em>θ</em>):
-cos²(<em>θ</em>) / (2 cos²(<em>θ</em>))
Cancel the cos²(<em>θ</em>) terms to end up with
(tan²(<em>θ</em>) cos²(<em>θ</em>) - 1) / (1 + cos(2<em>θ</em>)) = -1/2
