Find the natural logarithm of f(x), i.e. find l(x) = log(f(x)).?

Question

f(x) =
1
p2
exp−(x − μ)2
22 , x 2 <,−1 < μ < 1,  > 0.

Answer 1

1)ln 1=0
2)ln p^2= 2*ln p ( if p is positive) .In general ln p^2 = 2 ln I p I
3ln( exp(-(x-u)^2 = -(x-u)^2
I don't understand the meaning of the last line