Which of the following are exponential functions?
a. f(x)=10^4+3x
b. f(x)=(-5)^x
c. f(x)=(1/x)^6
d. f(x)=(1/4)^-2x

Question

Which of the following are exponential functions?
a. f(x)=10^4+3x
b. f(x)=(-5)^x
c. f(x)=(1/x)^6
d. f(x)=(1/4)^-2x

yanasidlinskiy · Answer

The variable is the exponent. If f(x) = ax, then we call a the base of the exponential function. So f(x) = 3x would be an example.. What do you think?

jadareese_18 · Answer

I'm confused still... @YanaSidlinskiy

eliesaab · Answer

any function of the form
$$
a^{u(x)}
$$
is exponential

eliesaab · Answer

You can see that b) is one.
There is another one. Which one?

eliesaab · Answer

Are you with me?

jadareese_18 · Answer

C. (1/x)^6 is also in the form of a^ux right? @eliesaab

jadareese_18 · Answer

Actually it would be choice D because in option C the x isn't used as a degree.

jadareese_18 · Answer

@eliesaab you were wrong.  One of the options wasn't B.  The answers were A and D.

eliesaab · Answer

@jadareese_18, Is A $ 10^4 +x$ or $ 10^{4+x} $?
It was written as  $ 10^4 +x$ and as such it is not exponential
B is also exponential