Answer:
8-8-21
Step-by-step explanation:
I think that is the answer
S4=935 found the infinite series
There are three things you have to know:
- A function is convex when its second derivative

- A function is concave when it second derivative

- The derivative of a power,
, is 
So, the first derivative is

and the second derivative is

This implies that the second derivative of a parabola is constant, and of course that 2 doesn't change the sign of
.
We have that
n----------> number of cities
the probability that the tourist will visit the cities in alphabetical order is (1/n<span>!)
P=</span>(1/n!)
n!-------------> (7*6*5*4*3*2*1)=5040
therefore
1/5040=0.000198-----------> (five decimal places)--------> 0.00020 (0.020%)
the answer is 0.00020 (0.020%)