Sketch the region in the plane consisting of points whose polar coordinates satisfy the given conditions: r≥0, π/3≤Ɵ≤2π/3 ?
just draw the x axis and implicit y -axis by a shaded line. (imagine that it is there to easily scale the angle. mark the point pi/3 and 2pi/3. link them with origin. the plane between two line is the required plane. Erase the shaded line. you have what you want