Exploring the Expression (x+3)/(x3)
The expression (x+3)/(x3) is a simple rational expression, meaning it's a fraction where both the numerator and denominator are polynomials. Let's dive into its properties and explore its behavior.
Domain and Restrictions
The first thing we need to consider is the domain of the expression. The domain represents the set of all possible values of x for which the expression is defined.
In this case, the expression is undefined when the denominator is zero. Therefore, we need to solve the equation:
x  3 = 0
This gives us x = 3. This means that x = 3 is a restriction on the domain of our expression. The domain can be expressed as:
x ∈ ℝ, x ≠ 3 (All real numbers except for 3)
Simplifying the Expression
The expression (x+3)/(x3) cannot be simplified further. It might be tempting to cancel out the 3 terms, but this is incorrect! We can only cancel common factors in the numerator and denominator, not individual terms.
Behavior and Asymptotes
The expression (x+3)/(x3) exhibits interesting behavior as x approaches certain values.

As x approaches 3 from the left (x < 3): The denominator becomes very small and negative, making the entire expression very large and negative. We say the expression approaches negative infinity.

As x approaches 3 from the right (x > 3): The denominator becomes very small and positive, making the entire expression very large and positive. We say the expression approaches positive infinity.

As x approaches positive or negative infinity: The numerator and denominator grow at roughly the same rate. The expression approaches a value of 1.
These behaviors are visualized by vertical asymptotes at x = 3 and a horizontal asymptote at y = 1.
Applications
This expression, while seemingly simple, can be used in various applications:
 Modeling RealWorld Phenomena: The expression can be used to model certain physical phenomena like the relationship between force and distance.
 Optimization Problems: It can be used in optimization problems where minimizing or maximizing a function is the goal.
 Calculus: The expression plays a role in understanding concepts like limits, continuity, and derivatives.
Conclusion
The expression (x+3)/(x3) may appear simple, but it holds within it the power to illustrate fundamental concepts in mathematics. By understanding its domain, restrictions, behavior, and asymptotes, we gain a deeper understanding of how rational expressions work and how they can be applied in various contexts.