Answer :
xlnx - x + c is the integral because ( xlnx - x + c )' = ( xlnx )' - x' + c' = ( x' )lnx +
x(lnx)'- 1 + 0 = 1lnx + x( 1 / x ) - 1 = lnx + 1 - 1 = lnx ;
x(lnx)'- 1 + 0 = 1lnx + x( 1 / x ) - 1 = lnx + 1 - 1 = lnx ;