a(n+2)=(2+cosnπ)(an -1)+3
if n is odd
a(n+2)=(2+cosnπ)(an -1)+3
a(n+2)=(2-1)(an -1)+3
= an +2
a(n+2) -an = 2
an - a1= n-1
an = n
if n is even
a(n+2)=(2+cosnπ)(an -1)+3
= 3(an -1)+3
a(n+2) = 3an
an/a2 = 3^[(n-2)/2]
an = 2. 3^[(n-2)/2]
ie
an = n ,if n is odd
=2. 3^[(n-2)/2] , if n is even
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