(1)(-∞,-1-2) subtraction function

(-1-√2,-1+√2) Incremental Function

(-1+√2, +∞) subtraction function

Through the second derivative of f "(x), the graph of f(x) can be drawn approximately.

(2) The second question, f(0) = 1.

Let the straight line g(x) = ax+1 intersect with (0, 1).

At x & gt=0, f (x)

That is, g (x) in x >; The region of =0 is above f(x), so it is easy to know the critical condition. The straight line is tangent to f(x) at (0, 1).

The tangent slope can be easily found as 1.

G(x) is easily obtained between swings, and a >；; = 1, g(x) in x >; The region =0 is above the level of f (x) and f(x).

So a > = 1