Question 1139229
{{{int((x))}}}{{{ dy}}} + {{{int((y))}}}{{{ dx}}}

since

{{{int((x))}}}{{{dy=xy+c}}}

{{{int((y))}}}{{{dx=xy+c}}}

then

{{{int((x))}}}{{{dy}}} + {{{int((y))}}}{{{dx}}}={{{2xy+2c}}}  where {{{c}}} is the constant of integration