Math Problem Statement

Find lim(h→0) [(f(5+h) - f(5))/h] if f(x) = 6x - 1. Simplify your answer.

Solution

We are asked to find the limit:

limh0f(5+h)f(5)h\lim_{h \to 0} \frac{f(5+h) - f(5)}{h}

where f(x)=6x1f(x) = 6x - 1.

Step 1: Substitute f(x)f(x) into the expression

We have f(x)=6x1f(x) = 6x - 1, so:

  • f(5+h)=6(5+h)1=30+6h1=29+6hf(5+h) = 6(5+h) - 1 = 30 + 6h - 1 = 29 + 6h,
  • f(5)=6(5)1=301=29f(5) = 6(5) - 1 = 30 - 1 = 29.

Step 2: Compute the difference

Now, compute f(5+h)f(5)f(5+h) - f(5): f(5+h)f(5)=(29+6h)29=6h.f(5+h) - f(5) = (29 + 6h) - 29 = 6h.

Step 3: Substitute into the limit expression

Substitute f(5+h)f(5)=6hf(5+h) - f(5) = 6h into the original limit: limh06hh.\lim_{h \to 0} \frac{6h}{h}.

Step 4: Simplify the expression

Simplify the expression: 6hh=6.\frac{6h}{h} = 6.

Step 5: Evaluate the limit

As h0h \to 0, the simplified expression is simply: limh06=6.\lim_{h \to 0} 6 = 6.

Thus, the solution to the limit is 6\boxed{6}.


Would you like further details or have any questions? Here are some related questions to extend the topic:

  1. What is the geometric interpretation of this limit?
  2. How does the derivative relate to this limit problem?
  3. What is the derivative of f(x)=6x1f(x) = 6x - 1 in general?
  4. Can the limit be solved using L'Hopital's Rule?
  5. How does this limit change if f(x)f(x) were a quadratic function?

Tip: The limit we just computed is the derivative of the function f(x)=6x1f(x) = 6x - 1 at x=5x = 5.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Derivatives

Formulas

Limit definition of the derivative: lim(h→0) [(f(a+h) - f(a))/h]

Theorems

Definition of the Derivative

Suitable Grade Level

Grades 11-12 (High School Calculus)