(x+1)分之1-(x²-1)分之1×(x+1)分之(x²-2x+1)
=(x+1)分之1-[(x+1)(x-1)]分之1×(x+1)分之(x-1)²
=(x+1)分之1-(x+1)²分之(x-1)
=(x+1)²分之(x+1)-(x+1)²分之(x-1)
=(x+1)²分之[(x+1)-(x-1)]
=(x+1)²分之2