设n为偶数.C^n_1p(1-p)^{n-1}+C^n_3p^3(1-p)^{n-3}+...=\alphaC^n_0(1-p)^n+C^n_2p^2(1-p)^{n-2}+...=\beta所以 [p-(1-p)]^n=\beta -\alpha即\beta -\alpha =(2p-1)^n另一方面\beta +\alpha =1所以 \beta =[(2p-1)^n...