欧拉公式:1+1/2+1/3+……+1/n=ln(n)+C,C为欧拉常数 数值是0.5772
1/2 + 3/4 + 5/6 + 7/8 + ...... + 199/200
= (1-1/2) + (1-1/4) + (1-1/6) + (1-1/8) + ......+ (1-1/200)
= (1+1+1+1+.....1) - (1/2+1/4+1/6+1/8+ ...... 1/200)
= 100 - 1/2(1+1/2+1/3+1/4+......+1/100)
= 100 - 1/2 ( ln100 + C )
≈ 100 - 1/2 ( 4.6052+0.5772 )
≈ 97.4088