1, a contains b (in b, 4n=2*2n=2*n(n belongs to z, z belongs to n, and z is an integer set)).

2.a contains B (equilateral triangle is a special case of isosceles triangle).

3.A contains B (the number in the root sign of Y in A must be greater than or equal to 0, so X+3 >; =0, so x & gt=-3, which should be X 2 in B, because X 2 >; =0, so x 2+1>; = 1, so y>= 1, and the range is less than a)

4、A=B