Question

Va rog 1 3 si 5.. si pe rand daca se poate . Adica sa scriu si eu in timp ce rezolvati

Answer 1

1. a3=5
a6=11
a6=a3+3r=>11=5+3r=>3r=6=>r=2
a9=a3+6r=>a9=5+12=17
2. f(1)=3
f(2)=4
f(3)=5
.........
f(20)=22
___________+
f(1)+f(2)+...+f(20)=[(3+22)20]/2=250
3. 4^(x+2)=2(x^2+5)=> 2^(2x+4)=2^(x^2+5)=>
=> 2x+4=x^2+5=>x^2-2x+1=0
Delta=4-4=0
x=2/2=1
4. (n+2)!/[(n+1)!1!]=2
n+2=2=>n=0