Answer:
The total number of U.S. high school students that played on a sports team that year can be estimated to be 7,950,000.
Step-by-step explanation:
From the random sample, we can expect that 
of all students played on a sports team that year. So in the bigger sample of 15900000 high school students, we can expect 
students to have played on a sports team that year.
Answer: 11.59 months
Step-by-step explanation:
You need to divide 339.12 by 29.26. Then you should check your answer by multiplying 11.59 by 29.26. Which should get you 339.1234. When you sound that you get 339.12. Hope this helps!!
The solutions appear to be
{π/2, 2π/3, 4π/3}.
_____
Replacing sin(2x) with 2sin(x)cos(x), you have
2sin(x)cos(x) +sin(x) -2cos(x) -1 = 0
sin(x)(2cos(x) +1) -(2cos(x) +1) = 0 . . . . factor by grouping
(sin(x) -1)(2cos(x) +1) = 0
This has solutions
sin(x) = 1
x = π/2and
2cos(x) = -1
cos(x) = -1/2
x = {2π/3, 4π/3}
