What is the value of x ?

Evaluate cos2θ for cosθ = square root of 3/2

Combine the information in the problem and the chart using the average balance method to solve the problem.

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?