logarit

V

v1xokun

ta có: [tex]{log}_{35}28=\frac{{log}_{14}28}{{log}_{14}35}[/tex]
[tex]= \frac{{log}_{14}7+2{log}_{14}2}{{log}_{14}7+{log}_{14}5}[/tex]
[tex]= \frac{{log}_{14}7+2{log}_{14}14-2{log}_{14}7}{{log}_{14}7+{log}_{14}5}[/tex]
[tex]= \frac{{-log}_{14}7+2}{{log}_{14}7+{log}_{14}5}= \frac{2-a}{a+b}[/tex]
 
Top Bottom