ABCDEF is a regular hexagon with point O as centre. Find the value of `vec(AB) + vec(AC) + vec(AD) + vec(AE) + vec(AF)`

Explanation

From the diagram
`(vec(AB) = -vec(DE)) (vec(BC) = - vec(EF))`
`vec(AB) + vec(AC) + vec(AD) + vec(AE) + vec(AF)`
`= cancelvec(AB)+(cancel vec(AB)+ cancel vec(BC))+vec(AD)+(vec(AD)+cancel vec(DE)) + (vec(AD) + cancel vec(DE) + cancel vec(EF))`
`= 3vec(AD) = 3(2vec(AO)) = 6(vec(AO))`