# Log help (Homework)

1. Oct 9, 2005

### Pepsi

I've been looking through my text book for a question even remotly similiar and no luck, if you could get me started witht this question I'd love to do it and then I'll write what I got and write it here.

If y=x^2(a+z) determine an expression equal to log x. (Hint: you will need to take the log both sides at some point)

2. Oct 9, 2005

### mezarashi

$$\log a^b = b\log a$$

3. Oct 9, 2005

### Pepsi

uhh not really, you could elaborate on that idea though?

Would it be like...

logx = xlog

then xlog^2(a+z)

Sorry I'm really confused/

4. Oct 9, 2005

### mezarashi

If you take the log of both sides, you end up with:

$$\log y = \log x^2^(^a^+^z^)$$

See the similarity between the b in my earlier equation and 2(a+z)? >_>

5. Oct 9, 2005

### Pepsi

okay... I kind of get it...

I did this...

log(y/x) = 2a + 2z

so thats logx = (2(a+z))/y

I'm still stuck

6. Oct 9, 2005

### mezarashi

The question asks, determine an expression for log x? I'm confused about what you are trying to accomplish. Following from:

$$\log y = \log x^2^(^a^+^z^)$$
$$\log x = \frac{\log y}{2(a+z)}$$

7. Oct 9, 2005

### Gokul43201

Staff Emeritus
Pepsi, please post all coursework related questions in the Homework Help section.

Also, you need to relearn the properties of logarithms first. Please go over this chapter in your text again. For instance, log(y)/log(x) is not the same as log(y/x).

Last edited: Oct 10, 2005