# I Calculation of x from log equation

1. Dec 4, 2017

### AligatorAmy

Hi

I have the following equation:
Log(x/y)=A*(e^z(-1))

I know values of y, A, z.
I need to calculate x from this equation.

I need to ‘extract’ x first therefore
Log(x)-Log(y)= A*(e^z(-1))
Log(x) = A*(e^z(-1)) +Log(y)
x=10^[ A*(e^z(-1)) +Log(y)]

I am not sure whether my formula modification is correct.
Thanks.

2. Dec 4, 2017

It looks correct to me, assuming the base of the $Log$ function is 10.

3. Dec 4, 2017

### Svein

Most of it is correct, but I am not sure of the line "x=10^[ A*(e^z(-1)) +Log(y)]". Using log10 is unusual in mathematics. Yes, I see that you do not write "ln(x/y)", but be sure to check what kind of logarithms you have.

4. Dec 4, 2017

### mathman

It would be simpler for calculation if you used y instead of 10^log(y), i.e. $$x=y\times 10^{A\times e^{z(-1)}}$$