1. Show that this expression is a total differential of the function u (x, y). Find u (x, y) function
1.3. - (1 / 2cos2y + ysin2x) dx + (xsin2y + cos2x + 1) dy

2. Solve the following tasks:
2.3. Find the coordinates of the center of mass homogenous quarter circle x2 + y2 = a2, lying in the first quadrant.

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