First, we rewrite the expression inside the summation:
1+k21000k2=1+k21000(1+k2−1)=1+k21000(1+k2)−1+k21000=1000−1+k21000. Therefore, we have
∑k=1∞1+k21000k2=∑k=1∞(1000−1+k21000)=∑k=1∞1000−∑k=1∞1+k21000. Since ∑k=1∞1000 diverges to infinity, we need to check if 1+k21000k2 converges to 0 as k→∞. We have limk→∞1+k21000k2=limk→∞1/k2+11000=1000=0. Therefore, by the divergence test, the series diverges.