Let a = {(x, y) / y = x ^ 2}, B = {(x, y) / y = 2 ^ x}, then the number of subsets a intersects B ()

It is easy to know that y = x ^ 2 and y = 2 ^ X have two intersections, that is, there are two elements in a ∩ B, so it has four subsets

Given the set u = {1, 2, 3, 4, 5, 6}, for the set a ⊆ u, define s (a) as the sum of all elements in a, then the sum s of all s (a)=______ ．

⊆ u = {1, 2, 3, 4, 5, 6}, a ⊆ u, then there are a total of C05 + C15 + C25 + C35 + C45 + C55 = 25 = 32 A with 1, and there are 32 A with 2, 3, 4, 5, 6, so s (a) = 32 × (1 + 2 + 3 + 4 + 5 + 6) = 32 × 21 = 672

Given the set a = {1,2,3}, for X contained in a, s (x) is defined as the sum of all elements in X, then the sum of all s (x) is and is
If the last half of the sentence is wrong, then the sum of all s (x) is uuuuuuuuuuuuuuuuuuuuuuuuuuy.

In other words, what is the sum of all elements of all subsets of a
Take element 1 for example, it will appear four times, so the answer is (1 + 2 + 3) * 4 = 24

Given the set a = {- 5, - 4, 0, 6, 7, 9, 11, 12}, X ⊆ a, define s (x) as the sum of elements in the set X, and find the sum s of all s (x)

The number of ⊆ x ⊆ a ⊆ x is 28. According to the properties of the subset of the set, there are 27 ⊆ s = (- 5-4 + 0 + 6 + 7 + 9 + 11 + 12) × 27 = 4608 in all the subsets

Given the set a = {0,1,2}, B = {1,2,3,4}, define a + B = (x, y) / X belongs to a intersection B, y belongs to a union B}, find the number of elements in a + B

A∩B={1,2}
A∪B={0,1,2,3,4}
A+B={(1,0)、（1,1）、（1,2）、（1,3）、（1,4）、（2,0）、（2,1）、（2,2）、（2,3）、（2,4）}

Let set a = {- 1, 0, 1}, set B = {0, 1, 2, 3}, define a * b = {(x, y) | x ∈ a ∩ B, y ∈ a ∪ B}, then the number of elements in a * B is ()
A. 7B. 10C. 25D. 52

According to the meaning of the question, we know that this question is a step-by-step counting principle, ∵ set a = {- 1, 0, 1}, set B = {0, 1, 2, 3}, ∩ a ∩ B = {0, 1}, a ∪ B {- 1, 0, 1, 2, 3}, ∪ X has two methods, y has five methods ∩ according to the multiplication principle, we get 2 × 5 = 10, so we choose B

Given a = {0, 1, 2, 3}, B = {(x, y) | x ∈ a, y ∈ a, X ≠ y, x + y ∈ a}, then the number of elements in B is ()
A. 3B. 6C. 8D. 10

When x = 0, y = 1, 2, 3; satisfy the set B. when x = 1, y = 0, 2; satisfy the set B. when x = 2, y = 0, 1; satisfy the set B. when x = 3, y = 0. Satisfy the set B. There are 8 elements in total. So select C

Given that a = {1,2,3} B = {1,2} defines a * b = {x | x = X1 + X2, X ∈ a, X ∈ B}, then the largest element in a * B is the number of all subsets of a * B

The largest element is 3 + 2 = 5
The number of all subsets is 2 ^ 5 = 32

The number of elements of set a = {x ∈ Z | y = 12x + 3, y ∈ Z} is ()
A. 4B. 5C. 10D. 12

According to the meaning of the problem, the elements in the set {x ∈ Z | y = 12x + 3 ∈ Z} satisfy that x is a positive integer and Y is an integer. From this, we can get x = - 15, - 9, - 7, - 6, - 5, - 4, - 2, - 1, 0, 1, 3, 9; at this time, the values of Y are: - 1, - 2, - 3, - 4, - 6, - 12, 12, 6, 4, 3, 3, 1 respectively. There are 12 qualified x, so we choose D

Given the set a = {0, 1, 2}, then the number of elements in the set B = {X-Y | x ∈ a, y ∈ a} is zero______ ．

X = 0, y = 0, X-Y = 0x = 0, y = 1, X-Y = - 1; X = 0, y = 2, X-Y = - 2; X = 1, y = 0, X-Y = 1; X = 1, y = 1, X-Y = 0; X = 1, y = 2, X-Y = - 1; X = 2, y = 0, X-Y = 2; X = 2, y = 1, X-Y = 1; X = 2, y = 2, X-Y = 0; {0, - 1, - 2, 1, 2}; the number of elements in B is 5

Let a = {(x, y) / y = x ^ 2}, B = {(x, y) / y = 2 ^ x}, then the number of subsets a intersects B ()