So you pressed f5 and then you went to intersection

Then you need to press enter two times to select the first and the second curve. Then come the bounds, this is what i do:

for lower bound i move my cursor so it would be on left side of intersection and then press enter and for upper bound move cursor to the right side of intersection(note when you move the cursor it is supposed to be on a line) then press enter and it should give you the intersection