f(n)=sin(nπ/4),n∈Z
最小正周期是T=2π/(π/4)=8
而一个周期内的和,根据对称性正负抵消为0
所以f(1)+f(2)+…+f(100)=f(1)+f(2)+f(3)+f(4)=sin(π/4)+sin(π/2)+sin(3π/4)+sin(π)=√2+1