>>880
nが偶数の時
∫tan(x)^ndx = x + Σ[k=1ton/2] (-1)^k {1/(2k-1)}tan(x)^(2k-1)

nが奇数の時
∫tan(x)^ndx = -(1/2)log(1+tan(x)^2) - Σ[k=1to(n-1)/2] (-1)^k {1/(2k)}tan(x)^(2k)