There's nothing to substitute, and no solution,
until somebody gives you another equation.
Step-by-step explanation:
sin(2x) = 2sin(x)cos(x)
2sin(x)cos(x) - cos(x) = 0
so one solution is cos(x) = 0.
=> x = pi/2 and 3pi/2 (90° and 270°)
for cos(x) <> 0 we have then
2sin(x) - 1 = 0
2sin(x) = 1
sin(x) = 1/2
=> x = pi/6 and 5pi/6 (30° and 150°)
Answer:
B. Of the people surveyed that were alive at the time, 90% of them knew exactly where they were when they heard the news.
Step-by-step explanation:
7th grade has 3 boy out of 10 students
probability of picking a boy is 3/10
8th grade has 9 boys out of 12 students are boys
probability of picking a boy is 9/12 reduced to 3/4
3/10 x 3/4 = 9/40 probability of picking 2 boys
