Simplify the following, where k represents any integer: cos(2kpi-(2kpi-x))
a. -cosx*sinx
b. (1/2)sin(2x)
c. cos((1/2)x)^2
d. cos(x)^2*sin(x)^2
e. undefined

Which expression is equivalent to 2x^2+7x+4?

What is the equation of a line passing through the point (6,1) and parallel to the line whose equation 3x=2y+4

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?