Describe the Region Whose Area Is Given by the Integral $$\int _ { 0 } ^ { x / 4 } \int _ { 0 } ^ { \cos 2 \theta } 2 r d r d \theta$$

Describe the region whose area is given by the integral.
$$\int _ { 0 } ^ { x / 4 } \int _ { 0 } ^ { \cos 2 \theta } 2 r d r d \theta$$