What you have posted means the following:
. . . . .[log<sub>2</sub>(unspecified argument)] × [8]
Did you actually mean the following?
. . . . .log<sub>2</sub>(8)
And what are the instructions? Are you supposed to integrate this expression over some interval?
Please reply with the full and exact text of the exercise, the complete instructions, and a clear listing of what you have tried and where you are stuck.
Thank you.
Eliz.