求教大神matlab问题，怎么修改以下语句

ab=sym('[xy,xy,xy,xy]');
ac=integral2(ab(3),0,1,0,1)

错误：
Error using integral2 (line 83)
First input argument must be a function handle.

integral2是计算数值积分的，前面为什么要把ab定义成符号量？
 
1、用符号积分
>> ab=sym('[x*y,x*y,x*y,x*y]');
>> ac=int(int(ab(3),0,1),0,1) 
ac = 
1/4
2、用数值积分：
>> ac=integral2(@(x,y)x*y,0,1,0,1)
ac =
    0.2500

syms x y s = solve((24.62*y^4 + 22.06*y^3 - 58.64*y^2 + 155.37*y - 24.62)*x^4 + (137.39*y^4 - 105.79*y^2 - 211.57*y - 31.60)*x^3 + (- 58.64*y^4 + 177.43*y^3 + 177.43*y - 58.64)*x^2 + (243.18*y^4 - 105.79*y^2 + 211.57*y - 137.39)*x - 24.62*y^4 + 155.37*y^3 - 58.64*y^2 + 22.06*y + 24.62==0 ,(23.52*y^4 + 272.3*y^3 - 90.0*y^2 + 272.3*y - 113.52)*x^4 + (259.36*y^4 - 259.36)*x^3 + (- 90.0*y^4 + 544.6*y^3 - 180.0*y^2 + 544.6*y - 90.0)*x^2 + (259.36*y^4 - 259.36)*x - 113.52*y^4 + 272.3*y^3 - 90.0*y^2 + 272.3*y + 23.52==0); 看结果用 s.x s.y