# Can I simply e^3x/e^2x ?

• December 30th 2011, 04:29 AM
angypangy
Can I simply e^3x/e^2x ?
If I have:

$y = \frac{e^3x + 4}{e^2x}$

Can I simply as you would eg with x^3/x^2?

Can I call it:

$y = e^x + \frac{4}{e^2x}$

What are the rules in simplifying these? Or can you not?

Angus
• December 30th 2011, 05:32 AM
earboth
Re: Can I simply e^3x/e^2x ?
Quote:

Originally Posted by angypangy
If I have:

$y = \frac{e^3x + 4}{e^2x}$

Can I simply as you would eg with x^3/x^2?

Can I call it:

$y = e^x + \frac{4}{e^2x}$

What are the rules in simplifying these? Or can you not?

Angus

1. I assume that you mean $y = \frac{e^{3x} + 4}{e^{2x}}$

2. Re-write the RHS as a product

$y = \frac{e^{3x} + 4}{e^{2x}}=\left( e^{3x} + 4 \right) \cdot \frac1{e^{2x}}$

3. Expand the RHS and cancel equal factors:

$\left( e^{3x} + 4 \right) \cdot \frac1{e^{2x}} = \frac{e^{3x}}{e^{2x}} + \frac4{e^{2x}}$
• December 30th 2011, 05:54 AM
HallsofIvy
Re: Can I simply e^3x/e^2x ?
Or write it as: $\left(e^{3x}+ 4\right)e^{-2x}= e^{3x- 2x}+ 4e^{-2x}= e^{x}+ 4e^{-2x}$.
• December 30th 2011, 06:29 AM
angypangy
Re: Can I simply e^3x/e^2x ?
Quote:

Originally Posted by HallsofIvy
Or write it as: $\left(e^{3x}+ 4\right)e^{-2x}= e^{3x- 2x}+ 4e^{-2x}= e^{x}+ 4e^{-2x}$.

That's what I thought but I put both into my TI calculator and it seemed to give different graphs. I must have done something wrong because they are the same now.