Y= -1/2x-2
this is the y=mx+b equation of a line.
Sin 2 x + sin x = 0
( sin 2 x = 2 sin x cos x )
2 sin x cos x + sin x = 0
sin x ( 2 cos x + 1 ) = 0
sin x = 0
x 1 = 0
x 2 = π
or: 2 cos x + 1 = 0
2 cos x = - 1
cos x = -1/2
x 3 = 2π/3
x 4 = 4π/3
Answer:
Angela is correct. Ricardo made a mistake which was that he probably got confused and did four times three plus two instead of four plus three times two.
Using the normal distribution, it is found that the replacement time that separates the top 18% from the bottom 82% is of 11.23 years.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
In this problem, the mean and the standard deviation are, respectively, given by
.
The desired value is the 82nd percentile, which is X when Z = 0.915, hence:


X - 9.4 = 0.915(2)
X = 11.23
The replacement time that separates the top 18% from the bottom 82% is of 11.23 years.
More can be learned about the normal distribution at brainly.com/question/24663213