Answer
$I^{\prime}\cap E$
Work Step by Step
$E\cap F$ represents the event that both $E$ and $F$ occur.
$E\cup F$ represents the event that $E$ occurs or $F$ occurs (or both)
The complement of $E,\ E^{\prime}$ represents the event that $E$ does not occur.
W: you will use the book's Website tonight,
I: your math grade will improve,
E: you will use the Website every night.\
-----------
(Your math grade will not improve) even though (you use the Website every night).
is equivalent to
(Your math grade will not improve) AND (you use the Website every night)
(I does not occur) AND (E occurs)
$I^{\prime}\cap E$
