Series combination of capacitors

The series combination of capacitors is shown in the following figure

From the figure, V1=Q/C1;
V2=Q/C2;
V3=Q/C3;
The potential difference across the series combination as
V=V1+V2+V3;
V=(Q/C1)+(Q/C2)+(Q/C3);
=Q(1/C1 + 1/C2 + 1/C3)
If C is the equivalent or effective capacitance of the series combination, and has the same charge Q, then C=Q/V and V=Q/C;
From the above equations,
Q/C =Q(1/C1 +1/C2 + 1/C3)
1/C=1/C1 +1/C2 +1/C3)
For 'n' number of capacitors,
1/C= 1/C1 +1/C2+.........+ 1/Cn
For two capacitors, the effective capacitance is
C=(C1C2 /C1+C2 )