If the sum of function value and derivative value of function f (x) = xlnx at x0 is equal to 1, then the value of x0 is equal to 1______ .

If the sum of function value and derivative value of function f (x) = xlnx at x0 is equal to 1, then the value of x0 is equal to 1______ .

If the definition field of function f (x) is (0, + ∞), and the derivative of function is f ′ (x) = LNX + X · 1x = 1 + LNX, then f (x0) + F ′ (x0) = 1, that is, 1 + lnx0 + xlnx0 = 1, then (x0 + 1) lnx0 = 0, and the solution is x0 = 1 or x0 = - 1 (rounding off), so x0 = 1, so the answer is: 1