If $j − 1 < logk < j$. Why is $j = O(log k)$?


If $ j∈Z$ + and $ k ∈ R$ + and $ j − 1 < logk < j$ . Why is $ j = O(log k)$ ? (All log’s are in base 2)

I know I have to find constants where $ j>=c*logk$ and $ j <= c*logk$ but I need some help with it.