Ok, let's do it :
f(x) = b*a^x + c
y - intercept 2, means, that for x = 0, then y = 2
f(0) = 2 = b + c
horizontal asymptote y = -2, means :
Lim ( b*a^x + c) = -2
x-----+/-infinity
a^x = e^(a*lnx)
Lim ( b*e^a*lnx + c)
if x --- - infinity, then :
b*a(1/infinity) + c = -2
b*0 + c = -2
c = -2
and b = 4
f(x) = 4*a^x - 2
Hope that helps
2007-04-10 09:44:36
·
answer #1
·
answered by anakin_louix 6
·
0⤊
1⤋
f(0) = ba^0 + c = b + c = 2 f(a million) = ba^a million + c = ab + c = 4 so ab - b = 2 because the horizontal asymptote is y = -2, all of us comprehend ba^x, which has y=0 as horizontal asymptote, has been translated down 2, so c = -2. then b - 2 = 2, b = 4, and 4a - 4 = 2 4a = 6 a = a million.5 so f(x) = 4(a million.5^x) - 2, answer d.
2016-11-28 03:12:10
·
answer #2
·
answered by ? 4
·
0⤊
0⤋
y = f(x) = ba^x + c
The y intercept is 2.
f(0) = 2 = bx^0 + c = b*1 + c = b + c
2 = b + c
c = 2 - b
a ≠ 0
The horizontal asymptote is y = -2. This is the value f(x) approaches as x→∞.
f(∞) = -2 = ba^∞ + c = ba^∞ + (2 - b)
The value of the function will be infinite unless |a| ≤ 1.
If |a| ≤ 1, then a^∞ = 0.
And we are left with:
-2 = 2 - b
b = 4
c = 2 - b = 2 - 4 = -2
So the function is
y = f(x) = 4a^x - 2
where | a | < 0 and a ≠ 0.
2007-04-12 13:31:22
·
answer #3
·
answered by Northstar 7
·
0⤊
0⤋