An exponential function is a function that can be written in the form
( x ) = A b x (x)=Ab^x ( x ) = A b x where A A A is a real number and b b b is a positive number not equal to one.
a)
g ( t ) = 5 ⋅ 3 t = ( 5 ) ( 3 ) t g(t)=\sqrt{5\cdot3^t}=(\sqrt{5})(\sqrt{3})^t g ( t ) = 5 ⋅ 3 t = ( 5 ) ( 3 ) t The function g ( t ) g(t) g ( t ) is exponential. A = 5 , b = 3 . A=\sqrt{5}, b=\sqrt{3}. A = 5 , b = 3 .
b)
f ( x ) = 3 e 2 x = ( 3 ) ( e 2 ) x f(x)=3e^{2x}=(3)(e^2)^x f ( x ) = 3 e 2 x = ( 3 ) ( e 2 ) x The function f ( x ) f(x) f ( x ) is exponential. A = 3 , b = e 2 . A=3, b=e^2. A = 3 , b = e 2 .
c)
u ( x ) = 2 x / 3 = ( 1 ) ( 2 3 ) x u(x)=2^{x/3}=(1)(\sqrt[3]{2})^x u ( x ) = 2 x /3 = ( 1 ) ( 3 2 ) x The function u ( x ) u(x) u ( x ) is exponential. A = 1 , b = 2 3 . A=1, b=\sqrt[3]{2}. A = 1 , b = 3 2 .
d)
v ( s ) = s x v(s)=s^x v ( s ) = s x The function v ( s ) v(s) v ( s ) is not exponential.
If x x x is a real number, then the function v ( s ) v(s) v ( s ) is power.
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