For Part B.
Rewrite P(Y>0|Y<1/2) to get an equivalent statement: 1-P(Y<=0|Y<1/2).
Now you can simply have a statement where you subtract a CDF (ie. P(Y<=0|Y<1/2)) from 1.
In getting the CDF, make sure that you adjust the PDF for Y to account for the conditional statement before you integrate. This adjustment will give you the PDF for Y|Y<1/2.
In other words, remember that the integral over all Y for every PDF must equal 1. So, since you know that Y must now be limited from -1 to 1/2, you can adjust the height of your PDF accordingly to still get 1 when you integrate over these new limits.
Then integrate, find this CDF and then subtact your answer from 1 to get the answer to the problem.
