Evaluate :
a2n+1×a(2n+1)(2n−1)an(4n−1)×(a2)2n+3
a2n+1×a(2n+1)(2n−1)an(4n−1)×(a2)2n+3=a2n+1×a(2n)2−(1)2a4n2−n×a2(2n+3)=a2n+1×a4n2−1a4n2−n×a4n+6=a2n+1+4n2−1−4n2+n−4n−6=a−n−6=a−(n+6)=1an+6