Question 38387
This is what is called "the change of base" formula...logb a= loga/ logb...the logs on the right side are to the base 10 (but could really be any base we choose)
In this case, 
log2 1000, our b = 2 and our a = 1000, so that
log2 1000 = log 1000 / log 2
log2 1000 = 3 / .30103 = 9.97 or almost 10
and that makes sense since
2^10 = 1024 and just about 1000