I need to find all values of the real parameter "a" for which the equation $\displaystyle \left| {a - \log x} \right| + \left| {a + \log x} \right| = 2$ has two solutions. Find the solutions.

Printable View

- Jan 10th 2013, 12:32 AMshervladLogarithmic equation with parameter, please help
I need to find all values of the real parameter "a" for which the equation $\displaystyle \left| {a - \log x} \right| + \left| {a + \log x} \right| = 2$ has two solutions. Find the solutions.

- Jan 10th 2013, 02:12 PMchiroRe: Logarithmic equation with parameter, please help
Hey shervlad.

Have you tried expanding out the absolute value to take care of all possible combinations?

Hint: a - log(x) + a + log(x) = 2 for a - log(x) > 0 and a + log(x) > 0 is 1 equation. Can you expand the rest and find the two common solutions? - Jan 10th 2013, 10:28 PMshervladRe: Logarithmic equation with parameter, please help
yeah...but that's a dead-end way. What I did was I sqared the equation and so I got rid of one module, and it is much easier to work with only one module than with two, especially having to variables...

If you are interested in the solution:

http://i.imgur.com/dv1a6.gif - Jan 10th 2013, 10:29 PMchiroRe: Logarithmic equation with parameter, please help
You might have to re-do it since the post says your equation is too long.