contestada

Determine each of the following.

(a) {x ∈ Z | 0 < x, x2 ≤ 100}

(b) |{x ∈ Z | 0 < x, x2 ≤ 100}|

(c) |{x ∈ Z | x > 10, x2 ≤ 100}

(d) {x ∈ Z | x > 10, x2 ≤ 100}|

(e) | P(A) | , where A is the set from Part a.

Respuesta :

Answer:

(a) [tex]\{1,2,3,4,5,6,7,8,9,10\}[/tex]

(b) 10

(c) [tex]\{\}[/tex]

(d) 0

(e) 1024

Step-by-step explanation:

(a)

A = {x ∈ Z | 0 < x, x² ≤ 100}

We need to find all the elements of given set.

The given conditions are

[tex]0<x[/tex]                ... (1)

[tex]x^2\leq 100[/tex]

Taking square root on both sides.

[tex]-\sqrt{100}\leq x\leq \sqrt{100}[/tex]

[tex]-10\leq x\leq 10[/tex]             .... (2)

Using (1) and (2) we get

[tex]0<x\leq 10[/tex]

Since x ∈ Z,

[tex]A=\{1,2,3,4,5,6,7,8,9,10\}[/tex]

(b)

We need to find the value of  | {x ∈ Z | 0 < x, x² ≤ 100}| or |A|. It means have to find the number of elements in set A.

[tex]|A|=10[/tex]

| {x ∈ Z | 0 < x, x² ≤ 100}| = 10

(c)

B = {x ∈ Z | x > 10, x² ≤ 100}

We need to find all the elements of given set.

The given conditions are

[tex]x>10[/tex]                ... (3)

[tex]x^2\leq 100[/tex]

It means

[tex]-10\leq x\leq 10[/tex]             .... (4)

Inequality (3) and (4) have no common solution, so B is null set or empty set.

[tex]B=\{\}[/tex]

(d)

We need to find the value of |{x ∈ Z | x > 10, x² ≤ 100}| or |B|. It means have to find the number of elements in set B.

[tex]|B|=0[/tex]

|{x ∈ Z | x > 10, x² ≤ 100}| = 0

(e)

We need to find the value of | P(A) |. P(A) is the power set of set A.

Number of elements of a power set is

[tex]N=2^n[/tex]

where, n is the number of elements of set A.

We know that the number of elements of set is 10. So the value of |P(A)| is

[tex]|P(A)|=2^{10}[/tex]

[tex]|P(A)|=1024[/tex]

Therefore |P(A)|=1024.