2log105 + log1036 - log109 =?

প্রশ্ন: 2log₁₀5 + log₁₀36 - log₁₀9 =?

সমাধান:
2log1₀5 + log₁₀36 - log₁₀9
= log₁₀5² + log₁₀6² - log₁₀3²            [ plog_kM = log_kM^p]
= log₁₀{(5² × 6²)/3²}             [log_kM + log_kN = log_k(MN), log_kM - log_kN = log_k(M/N)]
= log₁₀{(25 × 36)/9}
= log₁₀100
= log₁₀10²
= 2log₁₀10
= 2.1
= 2