Answer:
θ = 2π/3 or 5π/3
Step-by-step explanation:
2 cosθ + 1= 0
when + 1 goes to R H S Side than it becomes negative by transposition method
2 cos = -1
now by dividing by 2 both sides we get
cosθ = -
since cosθ is negative
Cosθ = - cos 60°
it means either cosθ lies in 2nd or third quadrant
θ = π - π/3
or
θ = 2π- π/3
so θ = 2π/3 or 5π/3
Answer:
With a .95 probability, the sample size that needs to be taken if the desired margin of error is .04 or less is of at least 216.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error:
For this problem, we have that:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
With a .95 probability, the sample size that needs to be taken if the desired margin of error is .04 or less is
We need a sample size of at least n, in which n is found M = 0.04.
With a .95 probability, the sample size that needs to be taken if the desired margin of error is .04 or less is of at least 216.