关于微积分z=(1+x.^2-y.^2).^0.5.*y 在y=x、x=-1、y=1区域内体积

>> [x,y]=meshgrid(-1:0.01:1,-1:0.01:1);
z=(1+x.^2-y.^2).^0.5.*y;
surf(x,y,z)
>> [x,y]=meshgrid(-1:0.025:1,-1:0.025:1);
>> z=(1+x.^2-y.^2).^0.5.*y;
>> mesh(x,y,z)
>> [X,Y]=meshgrid(-1:0.025:1);
>> [X,Z]=meshgrid(-1:0.025:1);Y=X;
>> hold on;mesh(X,Y,Z)
>> [X,Z]=meshgrid(-1:0.025:1);Y=ones(size(X));
>> hold on;mesh(X,Y,Z)
>> [Y,Z]=meshgrid(-1:0.025:1);X=-1.*ones(size(Y));
>> hold on;mesh(X,Y,Z)
完整的图形是这样的吧。。。1/2似乎很正常