Cos 45=7 under root 2 /AB
1 / Under root 2 = 7 under root 2 / AB
AB=14
Ans = 14(b)
Answer:
The sequence above is a geometric sequence
For an nth in a geometric sequence

where n is the number of terms
a is the first term
r is the common ratio
From the question
a = 45
r = 15 / 45
The explicit formula for the sequence is
U(n) = 45(1/3)^n-1
Hope this helps you