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**Janu42** For b), what do I draw? Mr F says: Integrate f(x, y) over the region that is under the line y = 2x but above the line y = 0 (that is, the x-axis).

For c), isnt it P(A union B)/ P(B)? Mr F says: No it's not. Did you look in your class notes at all. It's **intersection **(which is what matheagle's notation says) not union.

And how do I know what something like P(B) is? Integrate from 0 to 1 with X? Mr F says: Yes. Use the marginal density function.

Not exactly sure what to ask, but I'm still confused.

And for d), for the expectation part, do I just integrate with y * f(Y given x)? Mr F says: What do your class notes say to do?