in order to reduce the voltage and by doing so to limit the input voltage so the power dissipation will not be too much so the LDO will overheat.
i think there need to be something like this:
i can't see a reason why not to use this but i didn't see people using this technic
others suggest to use zener diode to limit the voltage in the input of LDO
http://www.evilmadscientist.com/2012/basics-introduction-to-zener-diodes/
As the LDO load increases, the divider output voltage decreases. In order to minimize that, you need a lot of current in the resistors. It is considered extremely wasteful of power.
i can't see a reason why not to use this
Well would the fact that it will not work change your mind?
The drive impedance into the LDR is too high and so you will need capacitors. But also :-
That heat has to go somewhere and if you are not dissipating it in the LDR then it is going into the resistors. What is more you need, as a rule of thumb, 10 times more current down the potential divider than you take out at the junction, so you use 10 times more power than you need.
KobiAflalo:
others suggest to use Zener diode/ to limit the voltage in the input of LDO
The concept of using a Zener Diode to turn a LDO regulator into a VHDO regulator truly makes my eyes water. Mind you, I am a bit sniffly already.
Otherwise, I am totally unable to improve on Mike's comments, except that I would have used some extra mark-up.
MorganS:
xyproblem.info
Good point, but his other posts and my comment to same are relevant. 
Use a switching regulator instead.