Part A Which of the following recursive functions defines the sequence described above?

A
f(1)=−18f(n)=4f(n+1), n>1f\left(1\right)=-18\newline f\left(n\right)=4f\left(n+1\right), \ n>1f(1)=−18
f(n)=4f(n+1), n>1
B
f(1)=−18f(n)=4+f(n+1), n>1f\left(1\right)=-18\newline f\left(n\right)=4+f\left(n+1\right) ,\ n>1f(1)=−18
f(n)=4+f(n+1), n>1
C
f(1)=−18f(n)=4+f(n−1), n>1f\left(1\right)=-18\newline f\left(n\right)=4+f\left(n-1\right) ,\ n>1f(1)=−18
f(n)=4+f(n−1), n>1
D
f(1)=−18f(n)=4f(n−1),n>1f\left(1 \right)=-18\newline f\left(n\right)=4f\left(n-1\right), n>1f(1)=−18
f(n)=4f(n−1),n>1

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

the 4th choice is the correct one

step-by-step explanation:

answer: 80,000

step-by-step explanation:

the population doubles every day.

10,000*2=20,000 day 4

20,000*2=40,000 day 5

40,000*2=80,000 day 6