是求1³+2³+...+n³?至少有三种方法.1. 由(n+1)^4-n^4 = 4n³+6n²+4n+1.n^4-(n-1)^4 = 4(n-1)³+6(n-1)²+4(n-1)+1(n-1)^4-(n-2)^4 = 4(n-2)³+6(n-2)²+4(n-2)+1...2^4-1 = ...