A formula is recursive if it expresses the term
in terms of the previous one(s) 
In this case, every term is 7 more than the previous one, so the formula for
will only involve
:

In fact, this formula is simply saying: for every index
, the term with that index is 7 more than the term before.
Also, we have to specify the starting point (otherwise we would go backwards indefinitely), so the complete recursive formula is

which means: start with 2 and generate every other term by adding 7 to the previous one.
I think it is always true. I am not sure but I hope I'm right
Answer:

Step-by-step explanation:
The identity you will use is:

So,


Now, using the difference of sin
Note: state that 

Solving the difference of sin:



Then,

Once

And,



Therefore,

Answer:
8, 0, -8, -12
Step-by-step explanation:
Answer:
1 + 1 = 2
Step-by-step explanation:
1 and 1 = 2 1 and 1 =2 1+1=2 1+1=2