延长MnPn-1交M1P1于N,如图,
∵当x=1时,y=1,
∴M1的坐标为(1,1);
∵当x=n时,y=1 / n ,
∴Mn的坐标为(n,1 / n );
∴S△P1M1 M2+S△P2M2M3+…+S△Pn-1Mn-1Mn=1/2
P1M1×P1M2+1 /2
M2P2×P2M3+…+1/2
Mn-1Pn-1×Pn-1Mn=1/2
(M1P1+M2P2+…+Mn-1Pn-1)=1/2 M1N=1/2(1-1/n)=n-1/2n
答案为n-1/2n
延长MnPn-1交M1P1于N,如图,
∵当x=1时,y=1,
∴M1的坐标为(1,1);
∵当x=n时,y=1 / n ,
∴Mn的坐标为(n,1 / n );
∴S△P1M1 M2+S△P2M2M3+…+S△Pn-1Mn-1Mn=1/2
P1M1×P1M2+1 /2
M2P2×P2M3+…+1/2
Mn-1Pn-1×Pn-1Mn=1/2
(M1P1+M2P2+…+Mn-1Pn-1)=1/2 M1N=1/2(1-1/n)=n-1/2n
答案为n-1/2n