There are an infinite number of solutions, so I don't plan to list them all.
I'll list two of them, and then describe how to get all of the rest.
You said that <u>2cos(x) - 1 = 0</u>
Add 1 to each side: 2cos(x) = 1
Divide each side by 2: cos(x) = 1/2
The angles whose cosine is 1/2 are 60 degrees, 300 degrees,
and any multiple of 360 degrees added to either of those.
Answer:
0.2709
Step-by-step explanation:
Since the sample size is large enough (np > 10 and nq > 10), we can estimate this with a normal distribution.
μ = p
μ = 0.68
σ = √(pq / n)
σ = √(0.68 (1 − 0.68) / 200)
σ = 0.033
x = 140 / 200
x = 0.7
Find the z score:
z = (x − μ) / σ
z = (0.7 − 0.68) / 0.033
z = 0.61
Use a calculator or table to find the probability.
P(Z > 0.61)
1 − P(Z < 0.61)
1 − 0.7291
0.2709