Find the equivalent capacient between `A` and `B`.

Explanation

(a) First, name the joints.
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This diagram is symmetrical about line `AB`, hence point on perpendicular of `AB` i.e.,`X`, `Y` and `Y` are at same potential, remove capacitors between `X` and `Y`,`Y` and `Z`.

(b)
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Symmetery about `AB`, points `X,Y` and `Z` are at same potential, remove capacitor between `X` and `Y,Y`and `Z`.

The diagram is symmetrical about perpendicular bisector of `AB`, therefore points `X,Y,Z` and `W` are at same potential. remove capacitor between `X` and `Y,Y` and `Z,Z` and `W`.