Math Is Fun Forum

Greaterpathmagician

Member

Registered: 2009-06-16

Posts: 32

Exponential functions

Hello

I am having trouble understanding exponential functions.
What does the formula F(x)= 4x mean and how do you work out the questions for Q.1 (b) by using the graph.

Help will be greatly appreciated

Thank you

Last edited by Greaterpathmagician (2009-08-09 00:40:33)

juriguen

Member

Registered: 2009-07-05

Posts: 59

Re: Exponential functions

Hi Greaterpathmagician

The function means that you asign the value 4 to the power of x to y = f(x).

So, for 1.a (I see some light lines, so you may have done, but just in case)

(i) 4^2 = 16
(ii) 4^1.5 = 8
(iii) 4^0.5 = 2

And for 1.b, you have to search the values the other way arround. Call the vertical axis y, and then:

(i) y = 1 -> x = 0
(ii) y = 4 -> x = 1
(iii) y = -2 -> you cannot find it. Indeed, 4^x is never < 0
(iv) y = 10 -> x around 1.7

Hope it helps!

---

“Make everything as simple as possible, but not simpler.” -- Albert Einstein

Greaterpathmagician

Member

Registered: 2009-06-16

Posts: 32

Re: Exponential functions

Thank you juriguen it helped me alot.