High School

Let \( f: \mathbb{N}^2 \to \mathbb{Z}^+ \) be defined as \( f(x, y) = 2^x 3^y \).

Which of the following best describes \( f \)?

A. Total and onto, and not one-to-one
B. Total and not one-to-one, and not onto
C. Total and one-to-one, and not onto
D. One-to-one and not onto, and not total
E. Onto and not one-to-one, and not total
F. One-to-one and onto, and not total
G. Not one-to-one and not onto, and not total
H. Total, one-to-one, and onto

Answer :

For given function f, f : N² --> Z⁺ be defined as

f(x,y) = 2ˣ3ʸ

Every element of domain(N²) has a unique image in co-domain but for every y∈Z⁺ there does not exit pair (p,q)∈N². Thus, the function f one to one and total but not onto function.

So, Correct option is option(C).

Onto Functions: A function in which every element of Co-Domain Set has one pre-image.

One-to-One Functions: A function in which one element of Domain Set is connected to one element of Co-Domain Set.

Total function: A function which is defined for all inputs of the right type, that is, for all of a domain.

Let f : N² --> Z⁺ be defined as

f(x,y) = 2ˣ3ʸ

then, f is not onto because for z∈ Z⁺

there is (x,y)∈N²

f(x,y) = z is not possible.

f is one to one because for (x₁, y₁) , (x₂,y₂)∈N²

such that f(x₁,y₁) = f(x₂,y₂)

=> 2ˣ¹3zʸ¹= 2ˣ²3ʸ²

=> x₁ = x₂ and y₁ = y₂

=>( x₁ ,y₁) = (x₂, y₂)

so, f is one to one. Every element of domain(N²) has an image in Co-domain(Z⁺). Thus, f is total function.

Hence, f is one to one and total but not onto.

To learn more about One-One and Onto function, refer:

https://brainly.com/question/11237515

#SPJ4

Final answer:

The function [tex]f(x, y) = 2^(3^x)[/tex] is total, onto, and not one-to-one.

Explanation:

The function [tex]f(x, y) = 2^(3^x)[/tex] is total, onto, and not one-to-one.

Let's break down each statement:

  1. Total: The function is total because it is defined for every pair of natural numbers (x, y).
  2. Onto: The function is onto because for every positive integer z, there exists a pair (x, y) such that f(x, y) = z. In other words, every positive integer has a pre-image under f.
  3. Not one-to-one: The function is not one-to-one because different pairs (x, y) can map to the same positive integer z. Therefore, there are multiple pre-images for some positive integers.