For f(x) to be continuous at x=π/2, the left-hand limit must equal the right-hand limit.
From the left (x≤π/2):
x→π/2−limf(x)=sin(2π)+n
=1+n
From the right (x≥π/2):
x→π/2+limf(x)=m⋅2π+1
=2mπ+1
Setting the two limits equal for continuity:
1+n=2mπ+1
n=2mπ
Substituting into sin2n:
sin(2n)=sin(2⋅2mπ)
=sin(mπ)
Since m∈Z, we have sin(mπ)=0 for any integer m.
Therefore, sin2n=0