Asked by Millie

Which function is increasing?
a. y = -2^x
b. y = 2 (1/2^x)
c. y = 3 (4^-x)
d. y = -4 (2^x)

What is the y-intercept of the function y = 4(2^x) - 2?
a. 2
b. -2
c. 4
d. 1

In the function y = 4(3^x) - 1, the graph is asymptotic to .....
a. y = 1
b. y - axis
c. y = -1
d. x - axis

Answers

Answered by Reiny
#1, none are increasing
http://www.wolframalpha.com/input/?i=plot+y+%3D+-2%5Ex+%2C+y+%3D+2+%281%2F2%5Ex%29+%2C+y+%3D+3+%284%5E-x%29+%2C+y+%3D+-4+%282%5Ex%29

2. for y-intercept , let x = 0
4(2^0) - 2
= 4(1) - 2
= 2

3. as x ---> +big 3^x get big , so the whole expression becomes larger and larger, thus no asymtpote there.
as x ----> -big, 3^x gets smaller and smaller
and the first term will become zero, leaving you with y = -1

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