Question

determinati al patrulea termen al progresiei aritmetice stiind ca a=1 si a2=4

Answer 1

4-1=3         r=3
a4=a1+3r=1+3*3=1+9=10

Answer 2

a₁ = 1  ;  a₂ = 1+ (2-1)ˣ3 = 4 => a₄ = 1+(4-1)ˣ3 = 1+3ˣ3 = 10  !