Trigonometry: Graphs

Problem : The point (0,0) lies on the graphs of which functions?

Problem : The point (0,1) lies on the graphs of which functions?

Problem : Which functions have a range of -1 to 1?

Problem : Which functions approach âàû and - âàû as θ approaches zero?

Problem : For which functions are the values between -1 and 1 not in the range?