f(x) = 2 + 3^{x }What isf(2x) - f(x)?

--------------------

It's embarrassing to ask about this question, but I can't remember how to solve it for the life of me. :(

Thanks in advance.

Printable View

- Sep 15th 2013, 09:56 PMFratricideSimple Exponential Equation
*f(x) = 2 + 3*^{x }What is*f(2x) - f(x)*?

--------------------

It's embarrassing to ask about this question, but I can't remember how to solve it for the life of me. :(

Thanks in advance. - Sep 15th 2013, 10:02 PMJJacquelinRe: Simple Exponential Equation
What have you done ?

First : f(2x)= ? - Sep 15th 2013, 10:12 PMFratricideRe: Simple Exponential Equation
I'm assuming that f(2x) = 2(2+3

^{x})? - Sep 15th 2013, 11:13 PMProve ItRe: Simple Exponential Equation
No. f(x) is a notation that says "the function operated on the value x". Here we are told $\displaystyle \displaystyle \begin{align*} f(x) = 2 + 3^x \end{align*}$, which says that whatever value you put in, is what you will raise 3 to the power of, and then add 2 to. So if instead we put in 2x we get f(2x). If the same function operates on 2x (so this is what we raise 3 to the power of and then add 2 to), what will we get?

- Sep 15th 2013, 11:34 PMJJacquelinRe: Simple Exponential Equation
- Sep 16th 2013, 03:42 AMFratricideRe: Simple Exponential Equation
Ah, thank you. Such a noob mistake.

Answer: 3^{x}(3^{x}-1)? - Sep 16th 2013, 05:02 AMProve ItRe: Simple Exponential Equation
No

- Sep 16th 2013, 09:46 AMJJacquelinRe: Simple Exponential Equation
- Sep 16th 2013, 11:36 AMHallsofIvyRe: Simple Exponential Equation
Tie breaker: "$\displaystyle 3^x(3^x- 1)$" is the correct answer to the

**original**question "what is f(2x)- f(x)". It is NOT the correct answer to the**last**question "what is f(2x)". - Sep 16th 2013, 12:40 PMJJacquelinRe: Simple Exponential Equation
OK. This is what I meant.

- Sep 17th 2013, 06:41 PMvotanRe: Simple Exponential Equation
- Sep 20th 2013, 05:20 PMvotanRe: Simple Exponential Equation