Answer:
where n>1
Step-by-step explanation:
Given

Required
Determine the recursive formula
The given sequence shows arithmetic progression (AP).
First, we calculate the common difference (d):


The recursive formula of an AP is determined using:
where 
Substitute 3 for d
where 
Let z be any number (like x would be)
if we set z equal to 2x-6y, then we get z = 2x-6y
The system
2x-6y = 8
2x-6 = 3
turns into this new system
z = 8
z = 3
but z is a single number. It can't be both 8 and 3 at the same time. So there are no solutions
The slope of AC is -0.4
Proof:
In triangles ABC and DBE,
∠DBE is common to both triangles.
AB = 2DB (D is the midpoint of the interval AB)
Also, BC = 2BE (E is the midpoint of the interval BC)
Thus triangles ABC and DBE are similar in the ratio 2:1
Since, they are similar, ∠BDE must equal ∠BAC (corresponding angles in similar triangles)
If ∠BDE = ∠BAC, DE must be parallel to AC (corresponding angles are equal along parallel lines)
Thus, the slope of AC = the slope of DE
Thus, the slope of AC is -0.4
Answer:

Step-by-step explanation:
Use the formula for a semicircle's perimeter.

Plug in 6 for d.

Let's use 3.14 for
, just to make it easier, but of course, if it states to round it to something else, just plug in that many values for
.

Answer:
40
Step-by-step explanation:
A quarter of 1600 is 400. A tenth of that is 40.
:P