Math Problem Statement

Suppose that f(x + h) - f(x) = -8hx^2 + 1hx - 8h^2x - 3h^2 + 3h^3. Find f'(x).

Solution

The problem you provided is asking to find f(x)f'(x), the derivative of the function f(x)f(x), given that:

f(x+h)f(x)=8hx2+1hx8h2x3h2+3h3.f(x + h) - f(x) = -8h x^2 + 1h x - 8h^2 x - 3h^2 + 3h^3.

This expression can be interpreted as the difference quotient, f(x+h)f(x)h\frac{f(x+h) - f(x)}{h}, from which we can derive f(x)f'(x).

Step-by-step Solution:

  1. Start with the definition of the derivative: f(x)=limh0f(x+h)f(x)h.f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}.

  2. Divide the given expression by hh: f(x+h)f(x)h=8hx2+1hx8h2x3h2+3h3h.\frac{f(x+h) - f(x)}{h} = \frac{-8h x^2 + 1h x - 8h^2 x - 3h^2 + 3h^3}{h}.

  3. Simplify the expression:

    • The first term simplifies to 8x2-8x^2.
    • The second term simplifies to 1x=x1x = x.
    • The third term becomes 8hx-8h x.
    • The fourth term simplifies to 3h-3h.
    • The fifth term becomes 3h23h^2.

    Therefore, the expression simplifies to: f(x+h)f(x)h=8x2+x8hx3h+3h2.\frac{f(x+h) - f(x)}{h} = -8x^2 + x - 8h x - 3h + 3h^2.

  4. Take the limit as h0h \to 0: As h0h \to 0, any terms involving hh will vanish. Specifically:

    • The term 8hx-8h x goes to 0.
    • The term 3h-3h goes to 0.
    • The term 3h23h^2 goes to 0.

    Therefore, the limit is: f(x)=8x2+x.f'(x) = -8x^2 + x.

Final Answer:

f(x)=8x2+x.f'(x) = -8x^2 + x.

Would you like further details on any step or have any questions? Here are five related questions to deepen your understanding:

  1. How does the difference quotient help in finding derivatives?
  2. What happens to higher-order terms of hh when taking the limit as h0h \to 0?
  3. Can you apply the same process to find f(x)f'(x) for a different function f(x)f(x)?
  4. What would the second derivative f(x)f''(x) be for this function?
  5. How can you use this method to find derivatives for more complex functions?

Tip: When dealing with limits in derivative calculations, remember that any term involving hh will vanish as h0h \to 0.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Derivatives

Formulas

f'(x) = lim(h -> 0) [f(x+h) - f(x)] / h

Theorems

Limit definition of a derivative

Suitable Grade Level

Grades 11-12 or Early College