Question

If a1=
1 and an=
(an-1)^2 + 2 then find the value of a4

Answer 1

123

Explanation:

`a_(1)=1\\a_(n)=(a_(n-1))^2+2\\a_(2)=(a_(1))^2+2=1^2+2=1+2=3\\a_(3)=(a_(2))^2+2=3^2+2=9+2=11\\a_(4)=(a_(3))^2+2=(11)^2+2=121+2=123`