Math Problem Statement

Given f(x) = 2x² + 5x-3, find f(x+h)-f(x)/h. h≠ 0.

Solution

To find f(x+h)f(x)h\frac{f(x+h) - f(x)}{h}, given f(x)=2x2+5x3f(x) = 2x^2 + 5x - 3, follow these steps:

Step 1: Find f(x+h)f(x + h)

We substitute x+hx + h into the function f(x)f(x):

f(x+h)=2(x+h)2+5(x+h)3f(x + h) = 2(x + h)^2 + 5(x + h) - 3

Expand the terms:

=2(x2+2xh+h2)+5(x+h)3= 2(x^2 + 2xh + h^2) + 5(x + h) - 3 =2x2+4xh+2h2+5x+5h3= 2x^2 + 4xh + 2h^2 + 5x + 5h - 3

Step 2: Calculate f(x+h)f(x)f(x+h) - f(x)

Now subtract f(x)f(x) from f(x+h)f(x + h):

f(x+h)f(x)=(2x2+4xh+2h2+5x+5h3)(2x2+5x3)f(x + h) - f(x) = \left(2x^2 + 4xh + 2h^2 + 5x + 5h - 3\right) - \left(2x^2 + 5x - 3\right)

Simplifying this:

=2x2+4xh+2h2+5x+5h32x25x+3= 2x^2 + 4xh + 2h^2 + 5x + 5h - 3 - 2x^2 - 5x + 3 =4xh+2h2+5h= 4xh + 2h^2 + 5h

Step 3: Divide by hh

Now, divide the expression by hh:

f(x+h)f(x)h=4xh+2h2+5hh\frac{f(x+h) - f(x)}{h} = \frac{4xh + 2h^2 + 5h}{h}

Simplifying:

=4x+2h+5= 4x + 2h + 5

Final Answer:

f(x+h)f(x)h=4x+2h+5\frac{f(x+h) - f(x)}{h} = 4x + 2h + 5

Let me know if you need further clarification or details.

Here are 5 follow-up questions related to this:

  1. What happens to the expression as h0h \to 0?
  2. How would you compute the derivative of f(x)f(x) using the limit definition?
  3. How does this result relate to the concept of the difference quotient?
  4. Can you find f(x)f'(x) using another method like power rule?
  5. How would the expression change if f(x)f(x) were a cubic function?

Tip: The expression f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} is often called the difference quotient, and it's a foundational concept for finding derivatives.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Difference Quotient
Quadratic Functions
Derivatives

Formulas

f(x) = 2x² + 5x - 3
f(x+h) - f(x) / h

Theorems

Difference Quotient Theorem

Suitable Grade Level

Grades 10-12