CBSEGrade 11MathematicsLimits and Derivatives

Derivative Dilemma?

Consider a function f(x) = (2x^2 - 5) / (x + 1). Can you find and interpret the derivative f'(x) to understand the rate at which the function's output changes when x = -2, given its physical implications for a car's acceleration on a specific road?

💬 1 answers0 votes👁 36 views21 July 2026

1 Answer

🤖
AI-Assisted Answer
0

📌 CONCEPT: The derivative f'(x) of a function f(x) represents the rate at which the function's output changes with respect to the input, which can be interpreted as the instantaneous rate of change or the slope of the tangent line to the function's graph at a given point. In the context of a car's acceleration, the derivative indicates how quickly the car's speed changes as it travels along a road. This helps in understanding the physical implications of the function on real-world scenarios.

📐 RULE / FORMULA: To find the derivative of a function, we can use the quotient rule, which states that if f(x) = g(x) / h(x), then f'(x) = (h(x)g'(x) - g(x)h'(x)) / h(x)^2. In this case, we have f(x) = (2x^2 - 5) / (x + 1).

💡 WORKED EXAMPLE: To find the derivative of f(x) = (2x^2 - 5) / (x + 1), we first identify g(x) = 2x^2 - 5 and h(x) = x + 1. Then, using the quotient rule, we find f'(x) = ((x + 1)(4x) - (2x^2 - 5)(1)) / (x + 1)^2. By simplifying this expression, we can find the derivative f'(x).

⚠️ COMMON MISTAKE: Students often make a mistake in applying the quotient rule, forgetting to multiply the numerator and denominator by the conjugate of the denominator or incorrectly simplifying the expression. Additionally, they may not consider the domain restrictions of the function and the derivative.

21 Jul 26