🔹 What is a Function?

• A function is a method/algorithm/process that turns an input into an output.

• Example:f(x)=x+3

  f(x)=x+3f(x) = x + 3

  • Input: any real number xxx
  • Output: x+3x + 3x+3

🔹 Domain, Codomain, and Mapping

• A → set of inputs (domain)

• B → set of possible outputs (codomain)

• A function is written as:f:A→B

  f:A→Bf : A \to B

🔹 What Calculus Studies

Calculus is about studying how the output of a function changes as we vary the input.

🔹 Example Problem

B(x)=100xB(x) = 100x

B(x)=100x

Where xxx is exposed skin area (in m2m^2m2).

👉 Question: How many bites will they get with x=0.3m2x = 0.3 m^2x=0.3m2 exposed?

Solution:

B(0.3)=100×0.3=30B(0.3) = 100 \times 0.3 = 30

B(0.3)=100×0.3=30