What is straight continues in both directions and does not end

Use set builder notation to represent the following set: { -3, -2, -1, 0}

Suppose a pendulum is l meters long. the time, t,in seconds that it tales to swing back and forth once is given by t=2.01

Simplify (1/2)4th power a. (1/16) b.(1/8) c.(1/4)