Question

÷2, 5, 8, 11,... Se cere an, n€(apartine)N* .....VA ROG MULT❤❤

Answer 1

Formula generala a termenului unei progresii aritmetice: an = a1 + (n-1)r
a1 = 2
a2 = 5
a2 - a1 = r ==> r = 3
an = 2 + 3(n-1) = 3n - 1

Answer 2

$\displaystyle \div~2,~5,~8,~11,...~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~a_n=?\\ \\ a_n=a_1+(n-1) \cdot r \\ \\ a_1=2,~r=3 \\ \\ a_n=2+(n-1) \cdot 3 \Rightarrow a_n=2+3n-3 \Rightarrow a_n=3n-1$