f(e^x) = e^x + x f(e^lnx) = e^lnx + lnx f(x) = x + lnx ∫ f(x) dx = ∫ x dx + ∫ lnx dx = x²/2 + xlnx - ∫ x * 1/x dx = x²/2 + xlnx - x + C
