Two men and four women line up at a checkout counter in a store.
(a) In how many ways can they line up???
(b) In how many ways can they line up if the first person line is
a woman and the line changes by gender. (w, m, w, w, m, w)??
n ∈ N and p is a prime number (p≥3).
a and b are defined by: a=2^n and
b=a×b. S(a) is the sum of divisors
of a and S(b) is the sum of divisors
of b.
1.Determinate the set of divisors of
a and the set of divisors of b.
2.show that S(a)+2^(n+1) =1+2S(a)
then calculate S(a).
3. write S(b) in function of S(a) then
calculate S(b).
U_(n ) is a sequence of real numbers
defined by U_0 =0 and for n ∈ N,
U_(n+1) =(√(U_n +6))
1. show that 0≤U_n ≤3.
2. show that U_(n ) is non−decreasing.
3. show that 3−U_(n+1) ≤((3−U_n )/3)
4. Deduct that 0≤3−U_(n+1) ≤((1/3))^n