1. what trig function has an amplitue of 1 and negative values for angles between π/2 and π?
2. what trig function never crosses the x-axis and has a value of 2 at π/6?
are these correct?
3. what trig function has a period of π and is undefined for -π/2, π/2, 3π/2...
4. what trig function has a period of 2π, is continuous, and is increasing for 0 < x < π/2?