An exponential function is written as F(x) = a x b^x, where the coefficient a is a constant, the base b is _____ but not equal to 1, and the exponent x is any number.

A. an integer
B. negative
C. real
D. positive

Question

An exponential function is written as F(x) = a x b^x, where the coefficient a is a constant, the base b is _____ but not equal to 1, and the exponent x is any number.

 		A.	an integer
 		B.	negative
 		C.	real
 		D.	positive

triciaal · Answer

usually positive whole number

anonymous · Answer

So D?

triciaal · Answer

never thought about it     sounds good to me

triciaal · Answer

@xapproachesinfinity , @jim_thompson5910  can we have a negative base for exponential functions?

jim_thompson5910 · Answer

you can, but only if the exponent is an integer. You run into problems if the exponent is a fraction or decimal number

jim_thompson5910 · Answer

so it's usually a good idea to make the base positive

anonymous · Answer

so stay with D?

jim_thompson5910 · Answer

yeah stay positive

xapproachesinfinity · Answer

i will always see a^x where a>0

triciaal · Answer

thanks guys

freckles · Answer

y=b^x has to have b as positive
consider b=-1
y=(-1)^x will not exist for all real x 
because example: (-1)^(1/2) is not real
y=(-1)^x does not fit the definition of exponential function

xapproachesinfinity · Answer

yeah a<0 would complicate things 
just taking extreme cases would prove that

anonymous · Answer

Sweet thanks :D

mertsj · Answer

Definition of Exponential Function

An Exponential Function is a function of the form y = ab^x, where both a and b are greater than 0 and b is not equal to 1.

jim_thompson5910 · Answer

'a' can be negative though for y = a*b^x

triciaal · Answer

@jim_thompson5910                 " where both a and b are greater than 0 "  so 'a' canNOT be negative

jim_thompson5910 · Answer

with y = a*b^x, only b has to be positive. The value of 'a' can be any real number you want.