Math Problem Statement

Ditentukan fungsi g: A → B yang didefinisikan sebagai diagram panah berikut.

Solution

The image shows a function g:ABg: A \to B defined by an arrow diagram. The function maps elements from set AA to set BB, where:

  • Set A={1,2,3,4}A = \{1, 2, 3, 4\}
  • Set B={1,2,3}B = \{1, 2, 3\}

The mappings are as follows:

  • g(1)=1g(1) = 1
  • g(2)=2g(2) = 2
  • g(3)=3g(3) = 3
  • g(4)=3g(4) = 3

We are asked to classify this function according to the provided options:

  1. A. Constant function: A constant function assigns the same value to every element in the domain, which is not the case here, as each element in AA is not mapped to the same value in BB.

  2. B. Surjective (onto) function: A surjective function is one where every element in the codomain BB has at least one preimage in AA. Here, every element in BB (1, 2, 3) is the image of some element in AA, so this function is surjective.

  3. C. Bijective function: A bijective function is both injective and surjective. Since this function is surjective but not injective (because both 3 and 4 map to 3, violating injectivity), it is not bijective.

  4. D. Injective (one-to-one) function: A function is injective if every element in the domain maps to a unique element in the codomain. Here, g(3)=g(4)=3g(3) = g(4) = 3, so it is not injective.

  5. E. Linear function: A linear function typically applies to real numbers and is of the form g(x)=ax+bg(x) = ax + b. This function involves finite sets, so it doesn't apply here.

Conclusion:

The function is surjective (B).

Do you need further clarification, or have any questions?

Here are 5 related questions for further exploration:

  1. What is the difference between an injective and a surjective function?
  2. How do you determine if a function is bijective from its arrow diagram?
  3. Can a function be both injective and surjective, and what does that mean?
  4. How would this function change if an element from set BB was not mapped to any element from AA?
  5. What real-world examples can represent surjective functions?

Tip: When analyzing functions from a diagram, check carefully if every element in the domain and codomain is accounted for to classify the function correctly.

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Math Problem Analysis

Mathematical Concepts

Functions
Injective and Surjective Functions
Arrow Diagrams

Formulas

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Theorems

Surjective Function Theorem

Suitable Grade Level

Grades 10-12