[6x*(x^2-1)^2]′
=6x′*(x^2-1)^2+6x*[(x^2-1)^2]′
=6*(x^2-1)^2+6x*2（x^2-1）*（x^2-1）′
=6*(x^2-1)^2+12x*（x^2-1）*2x
=6*(x^2-1)^2+24x^2(x^2-1)
=6*(x^2-1)(x^2-1+4x^2)
=6(x^2-1)(5x^2-1)