Respuesta :
Answer:
{x\ x e U and x has a negative square root} is an empty set.
Step-by-step explanation:
If x e U, x is a negative real number, and they don't have a square root (they don't have even roots). Their square roots are complex numbers, not real ones.
Answer:
Option B.
Step-by-step explanation:
Consider,
[tex]U=\{x|x\text{ is a negative real number }\}[/tex]
We need to find the empty set from the given options.
In option A,
Let [tex]S_1=\{x|x\in U\text{ and }x \text{ has a negative cube root}\}[/tex]
Since x has a negative cube root, it means x is a negative real number. So, this set is not an empty set.
In option B,
Let [tex]S_2=\{x|x\in U\text{ and }x \text{ has a negative square root}\}[/tex]
Since x has a negative square root, it means x is a positive real number because square root of a negative number is an imaginary number. So, this set is an empty set.
In option C,
Let [tex]S_3=\{x|x\in U\text{ and }x \text{ is equal to the product of a positive number and -1}\}[/tex]
Since x is equal to the product of a positive number and -1, it means x is a negative real number. So, this set is not an empty set.
In option D,
Let [tex]S_4=\{x|x\in U\text{ and }x \text{ is equal to the sum of one negative and one positive number}\}[/tex]
Since x is equal to the sum of one negative and one positive number, it means x can be a negative real number or positive real number. So, this set is not an empty set.
Hence, option B is correct.