y1 and y2 are equal. That's because
The graph of y = csc(x) from 0 to 2p is
Each marked unit on the y-axis is 1.
You question:
What is the value for y1 and y2? doesn't make sense because functions have many values. In fact
most functions, including this one, have infinitely many values,
a different value of y for every value of x.
Edwin