Question

Diketahui ^5 log 3=a dan ³log 4 =b maka ⁴log 15=

Answer 1

^5 log 3 = a
^3 log 5 = 1/a
^3 log 4 = b
^4 log 3 = 1/b

^4 log 15
= ^4 log (3 . 5)
= ^4 log 3 + ^4 log 5
= ^4 log 3 + ^4 log 3 . ^3 log 5
= ^4 log 3 (1 + ^3 log 5)
= 1/b (1 + 1/a)
= 1/b + 1/ab
= (a + 1) / ab