1)f'(x)=-sinx+x=0=>sinx=x=>x=0
x _______________0________________
f'(x)-------------------------1++++++++++++++
f(x) descrescatoare crescatoare
x=0 este punct de minim adica f(x)≥f(0)=>f(x)≥1
2)Pentru a determina inversa functiei f, rezolvam ecuatia f(x)=y in x.
[tex]f(x)=y\\
2^x+3=y\\
2^x=y-3\\
log_{2}2^x=log_{2}(y-3)\\
x=log_{2}(y-3)\\
g(x)=log_{2}(x-3)\\
g(5)=log_{2}(5-3)=log_{2}(2)=1[/tex]
