分子分母乘以5-1(平方差公式配平) 原式=(5-1)(5+1)(5^2+1)(5^4+1)(5^8+1)(5^16+1)/(5-1)+1/4 =(5^2-1)(5^2+1)(5^4+1)(5^8+1)(5^16+1)/4+1/4 =[(5^4-1)(5^4+1)(5^8+1)(5^16+1)+1]/4 =[(5^8-1)(5^8+1)(5^16+1)+1]/4 =[(5^16-1)(5^16+1)+1]/4 =[(5^32-1)+1]/4 =5^32/4