ove Proposition 3.5 (ii). Let f be an extended real-valued function defined on a measurable set E. uppose D CE is measurable. Then f is measurable on E if and only if the restrictions f|p and fE\D e both measurable.

.0 4. -1- X-аxis -2 -3+ -4- 0.5 -2 O -0.5 to 2) 1. y-axis

Where a > 0 and b > 0, the graph of the circle x2 + y2 = b2 contains point X in Quadrant II with x-coordinate −a. It also contains a second point Y in Quadrant IV where x = a. Find an expression for the length of XY in terms of a and b. XY=