Equations

[fairwinds]

Hi,

Trying to help my daughter with her homework... long time since school...

Does anyone remember how to solve equations like:

2^SQRT(x)=8

 

[Andrew Fergus]

Hi

From what I (vaguely) remember you first need to convert the right side of the equation to the same format, i.e. 2^n. BUT that assumes you know the 2^i (for i = 1 to n) sequence of numbers. Anyway, I found (what may be) an interesting link here:
http://www.purplemath.com/modules/solvexpo.htm

Andrew

 

[fairwinds]

Thanks Andrew!

The link was spot on.

It's scary how you forget these things...

 

[Oaktree]

You could also do:

2^(sqrt x) = 8
ln(2^(sqrt x)) = ln(8)
(sqrt x) * ln(2) = ln(8)
sqrt x = ln(8)/ln(2)
sqrt x = 3
x = 3^2
x = 9

edit: nvm, that's on page 2 of the link Andrew provided

 

[fairwinds]

Hi Oaktree!

Actually she (my daughter) has not learnt about logarithms yet. I think it's next year or so, so I guess they were after the first option.

Thanks anyway!