测试
(15*a^2*b*c*(-b+c)^2/2+15*a^2*b*c*(b-c)^2/2+15*a*b^2*c*(-a+c)^2/2+15*a*b^2*c*(a-c)^2/2+15*a*b*c^2*(-a+b)^2/2+15*a*b*c^2*(a-b)^2/2+a*(-b+c)^2*(6*a*c+7)/6+a*(-b+c)^2*(27*a^3*c+17*a+2*b)/3+a*(b-c)^2*(6*a*b+7)/6+a*(b-c)^2*(27*a^3*b+17*a+2*c)/3+b*(-a+c)^2*(6*b*c+7)/6+b*(-a+c)^2*(2*a+27*b^3*c+17*b)/3+b*(a-c)^2*(6*a*b+7)/6+b*(a-c)^2*(27*a*b^3+17*b+2*c)/3+c*(-a+b)^2*(6*b*c+7)/6+c*(-a+b)^2*(2*a+27*b*c^3+17*c)/3+c*(a-b)^2*(6*a*c+7)/6+c*(a-b)^2*(27*a*c^3+2*b+17*c)/3+(3*a*b*c-a*b-a*c-b*c)*(27*a^3*b^2+27*a^3*b*c+81*a^2*b^3*c+81*a^2*b*c^2+27*a*b*c^2+3*a*c^2+35*a+34*b*c+c^2+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^2*b*c^2+27*a^2*b*c+3*a^2*c+a^2+81*a*b^3*c^2+27*a*b*c^3+34*a*b+27*b^2*c^3+35*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^2*b^2*c+27*a^2*b*c+3*a^2*b+a^2+27*a*b^3*c+81*a*b^2*c^3+34*a*c+27*b^3*c^2+35*b+14)/3+(3*a*b*c-a*b-a*c-b*c)*(27*a^3*b*c+27*a^3*c^2+81*a^2*b^2*c+81*a^2*b*c^3+27*a*b^2*c+3*a*b^2+35*a+b^2+34*b*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^3*b*c^2+27*a^2*c^3+81*a*b^2*c^2+27*a*b^2*c+27*a*b*c^3+34*a*b+3*b^2*c+b^2+35*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^3*b^2*c+27*a^2*b^3+27*a*b^3*c+81*a*b^2*c^2+27*a*b*c^2+34*a*c+3*b*c^2+35*b+c^2+14)/3)/(3*a^2*b+3*a^2*c+3*a*b^2+4*a*b+3*a*c^2+4*a*c+3*b^2*c+3*b*c^2+4*b*c)
(15*a^2*b*c*(-b+c)^2/2+15*a^2*b*c*(b-c)^2/2+15*a*b^2*c*(-a+c)^2/2+15*a*b^2*c*(a-c)^2/2+15*a*b*c^2*(-a+b)^2/2+15*a*b*c^2*(a-b)^2/2+a*(-b+c)^2*(6*a*c+7)/6+a*(-b+c)^2*(27*a^3*c+17*a+2*b)/3+a*(b-c)^2*(6*a*b+7)/6+a*(b-c)^2*(27*a^3*b+17*a+2*c)/3+b*(-a+c)^2*(6*b*c+7)/6+b*(-a+c)^2*(2*a+27*b^3*c+17*b)/3+b*(a-c)^2*(6*a*b+7)/6+b*(a-c)^2*(27*a*b^3+17*b+2*c)/3+c*(-a+b)^2*(6*b*c+7)/6+c*(-a+b)^2*(2*a+27*b*c^3+17*c)/3+c*(a-b)^2*(6*a*c+7)/6+c*(a-b)^2*(27*a*c^3+2*b+17*c)/3+(3*a*b*c-a*b-a*c-b*c)*(27*a^3*b^2+27*a^3*b*c+81*a^2*b^3*c+81*a^2*b*c^2+27*a*b*c^2+3*a*c^2+35*a+34*b*c+c^2+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^2*b*c^2+27*a^2*b*c+3*a^2*c+a^2+81*a*b^3*c^2+27*a*b*c^3+34*a*b+27*b^2*c^3+35*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^2*b^2*c+27*a^2*b*c+3*a^2*b+a^2+27*a*b^3*c+81*a*b^2*c^3+34*a*c+27*b^3*c^2+35*b+14)/3+(3*a*b*c-a*b-a*c-b*c)*(27*a^3*b*c+27*a^3*c^2+81*a^2*b^2*c+81*a^2*b*c^3+27*a*b^2*c+3*a*b^2+35*a+b^2+34*b*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^3*b*c^2+27*a^2*c^3+81*a*b^2*c^2+27*a*b^2*c+27*a*b*c^3+34*a*b+3*b^2*c+b^2+35*c+14)/3+(3*a*b*c-a*b-a*c-b*c)*(81*a^3*b^2*c+27*a^2*b^3+27*a*b^3*c+81*a*b^2*c^2+27*a*b*c^2+34*a*c+3*b*c^2+35*b+c^2+14)/3)/(3*a^2*b+3*a^2*c+3*a*b^2+4*a*b+3*a*c^2+4*a*c+3*b^2*c+3*b*c^2+4*b*c)
