Exponential Functions Question

Hi there, I'm trying to do this question but I'm stuck:

Graph the function:

f(x) = (2/3)^{x}, -4≤x≤1, x∈R

f(-2) lies in the range [1, a]. If a ∈ N, then what is the minimum value of a?

I've drawn the graph, but I don't understand the second part of the question. Could someone please help me?(Nod)

Re: Exponential Functions Question

Quote:

Originally Posted by

**HelenMc9** Graph the function:

f(x) = (2/3)^{x}, -4≤x≤1, x∈R

f(-2) lies in the range [1, a]. If a ∈ N, then what is the minimum value of a?

I've drawn the graph, but I don't understand the second part of the question. Could someone please help me?

$\displaystyle a = \left\lceil {f( - 2)} \right\rceil $, that is ceiling function.

Re: Exponential Functions Question

You are asked to find the smallest natural number *a* such that f(-2) ≤ *a*.

Re: Exponential Functions Question

Sorry I don't get it, I'm still really confused ...

Re: Exponential Functions Question

Quote:

Originally Posted by

**HelenMc9** Sorry I don't get it, I'm still really confused ...

What does $\displaystyle f(-2)=~?$

Re: Exponential Functions Question

Re: Exponential Functions Question

Quote:

Originally Posted by

**HelenMc9** 2.25?

OK what is the smallest $\displaystyle a\in\mathbb{N}$ so that $\displaystyle f(-2)\in[1,a]~?$

Re: Exponential Functions Question

Eh ... I don't know. What does ' f(-2) ∈ [1,a] ' mean? :/

Re: Exponential Functions Question

Quote:

Originally Posted by

**HelenMc9** Eh ... I don't know. What does ' f(-2) ∈ [1,a] ' mean? :/

**You cannot do these questions if you don't know the **__basics__

It means $\displaystyle 1\le f(-2)\le a$.