设20cm的绳子剪成两段为x,20-x两个正方形的面积分别为（x/4)^2=1/16*x^2[(20-x)/4]^2=25-5/2x+1/16*x^2设两个正方形的面积和为yy=1/16*x^2+25-5/2x+1/16*x^2=1/8*x^2-5/2x+25=1/8(x-10)^2+25/2所以当x=10,即20cm的绳...