Answer:
an = 4n +5
Step-by-step explanation:
First we need to find a common difference
d = a2-a1 = 13-9 = 4
The formula for an
an =a1+d(n-1)
an = 9 + 4(n-1)
Distributing
an = 9+4n-4
Combine like terms
an = 4n +5
Plug in 6 for x and solve out for f(x)
Let
In order to prove this by induction, we first need to prove the base case, i.e. prove that P(1) is true:
So, the base case is ok. Now, we need to assume 
and prove 
.
states that
Since we're assuming , we can substitute the sum of the first n terms with their expression:
Which terminates the proof, since we showed that
as required
For this case what you should see is each of the edges of the prism that are parallel.
We then have as parallel edges:
AC and GE
CG and AE
CD and GH
AB and EF
BD and HF
DH and BF
CD and EF
GH and AB
Answer:
8 pairs of parallel lines
