Question

Se Noteaza cu g inversa funcției bijective f:(0, plus infinit) -> (4, plus infinit) , f(x) = 2 la puterea x + 3. Determinati g(5)

Answer 1

g:(4  ,∞)→(0,∞)
fog(x)=f(g)(x)=x=>
2^g(x)+3=x=>2^g(x)=x-3 logaritmam  ambii  termeni  si  obtinem
log[2]g(x)=log[2](x-3)    log[2]=  logaritm  in  baza  2
g(x)=log[2](x-3)
g(5)=log[2]2=1