Which of the following best describes the following set of numbers? 2, -2, 2, -2, ...

Finite arithmetic sequence
Infinite geometric sequence
Finite geometric sequence
Infinite arithmetic sequence

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.