原式可以这样做原式=(1-p)(1-p)(1-p)=(1-p)的平方(1-p)=(1-2p+p的平方)(1-p)=1-2p+p的平方-p+2p的平方-p的3次方=1-3p+3p的平方-p的3次方
(1-p)³=(1-p)²(1-p)=(1-2p+p²)(1-p)=1-2p+p²-p+2p²-p³=1-3p+3p²-p³
(1-p)^3=(1-p)(1-p)^2=(1-p)(1-2p+p^2)=1-3p+3p^2-p^3