On the segment x ∈ [0,10] plot the numerical solution of the equation y '+ y = 2xsiny, satisfying the initial condition y (0) = 1.
What is wrong here? My solution:

Calculate  where the domain Ω is bounded by the surfaces x + y + z = 1, x = 0, y = 0, z = 0.

What am I doing wrong?

Task: Calculate   where Ω is the part of a circle of radius a centered at
point O (0; 0), lying in the first quarter.

My attempt to solve:

What values need to be taken instead of infinity?

Calculateif 

Determine which of the limits exist and calculate 
if