（x+1分之x+1）除以（1- 1-x²分之3x平方）乘以x-1分之1
=[x/(x+1)+1]÷[1+3x²/(x²-1)]*1/(x-1)
=(x+x+1)/(x+1)÷(x²-1+3x²)/(x-1)(x+1)*1/(x-1)
=(2x+1)*(x-1)/(x²+3x²-1)*1/(x-1)
=(2x+1)/(4x²-1) .
=(2x+1)/(2x+1)(2x-1) x=4分之根号6
=1/(2x-1)
=1/(1/2√6-1)
=(1/2√6+1)/(3/2-1)
=(1/2√6+1)/(1/2)
=2+√6