initial conditions question..

[nabliat6]

https://i48.tinypic.com/1o4ow9.jpg

why in this circuit they say that in t<0
the voltage on both capacitators is 12 volts??

if both points of each capacitators is connected to the voltage source directy
then 12 volts is ok.

but here we have a resistor between them
this resistor drops the original voltage
it cannot be 12

 

[Grossel]

https://i48.tinypic.com/1o4ow9.jpgwhy in this circuit they say that in t<0
the voltage on both capacitators is 12 volts??

Because they assume that the caps is already charged when measurements starts.

if both points of each capacitators is connected to the voltage source directy
then 12 volts is ok.

Yes. There will be no potential difference, and no current flow either.

but here we have a resistor between them
this resistor drops the original voltage
it cannot be 12

With respect to ground, yes - that will measure 12V.