Question

se log3=a e log7=b, calcule log✓21

Answer 1

$log( \sqrt{21 } ) = log( \sqrt{3 \times 7} ) = log( \sqrt{3} ) \times log( \sqrt{7} ) = { log(3) }^{ \frac{1}{2} } + { log(7) }^{ \frac{1}{2} } = \frac{1}{2} \times ( log(3) + \frac{ {1} }{2} log(7) = \frac{1}{2} \times (a + b)$