I.1.49 Double Integrals

Condition: a double integral \ (\ iint_ {d} f (x, y) d x d y \) in the region \ (d \). a) Write it in the form of a repeated integral in the decartre coordinates, b) change the integration procedure, c) go to the polar coordinates. \ [\ left \ {\ begin {arry} {c} 0 \ leq y \ leq 3 \\ \ sqrt {6 y-y^} \ leq x \ leq 3 \ ent {arry} \ right. \]