log2 + log16 + log512 + --- --- --- ধারাটির ১ম 7টি পদের সমষ্টি কত?

log2 + log16 + log512 + --- --- ---
= log2 + log24 + log29 + --- --- ---
= log2 + 4log2 + 9log2 + --- --- ---
= (1 + 4 + 9 + --- --- --- )log2
= (1¹ + 2² + 3² + --- --- --- + 7²)log2
= [7(7 + 1)(2 × 7 + 1)/6] log2
= [7 × 8 ×15/6] log2
= 140 log2