因a^4+1/4=(a^4+a^2+1/4)-a^2=(a^2+1/2)^2-a^2=(a^2+a+1/2)(a^2-a+1/2) 用此法将各式写成:1^4+1/4=1/2*5/2 2^4+1/4=5/2*13/2 3^4+1/4=13/2*25/2 .原式=1/2*5/2*13/2*25/2*.*685/2*761/2÷5/2*13/2*25/2.761/2*841/2 ...