Hi !

Ouch !A) P(A)uP(B)

u is used for sets, not for numbers such as P(A) and P(B)

"either A or B or both" is equivalent to A u B

But in general, P(A u B)=P(A)+P(B)-P(A n B) (see a Venn diagram for understanding)

No, what you wrote is "A and B"B) P(AnB)

either A or B but not both : please look at the sketch.

You want the grey and the blue parts and only them.

See what its complement is : orange and green parts --> (A u B)' u (A n B)=(A' n B') u (A n B)

So either A or B but not both is : [(A u B)' u (A n B)]'

Good luck