Math Problem Statement

For the function f(x)=-6x2-2x+5 , evaluate and fully simplify each of the following.

f(x+h)

f(x+h)-f(x)h

Solution

Let's start by analyzing and evaluating each part of the given expressions.

Function: f(x)=6x22x+5f(x) = -6x^2 - 2x + 5

1. Evaluate f(x+h)f(x+h):

To find f(x+h)f(x+h), we need to substitute x+hx+h into the function in place of xx.

f(x+h)=6(x+h)22(x+h)+5f(x+h) = -6(x+h)^2 - 2(x+h) + 5

Now expand and simplify:

  • Expand (x+h)2=x2+2xh+h2(x+h)^2 = x^2 + 2xh + h^2: f(x+h)=6(x2+2xh+h2)2(x+h)+5f(x+h) = -6(x^2 + 2xh + h^2) - 2(x+h) + 5
  • Distribute: f(x+h)=6x212xh6h22x2h+5f(x+h) = -6x^2 - 12xh - 6h^2 - 2x - 2h + 5

This is the simplified form of f(x+h)f(x+h):

f(x+h)=6x212xh6h22x2h+5f(x+h) = -6x^2 - 12xh - 6h^2 - 2x - 2h + 5

2. Evaluate f(x+h)f(x)h\frac{f(x+h) - f(x)}{h}:

Now, let's calculate the difference f(x+h)f(x)f(x+h) - f(x) and then divide by hh.

[ \frac{f(x+h) - f(x)}{h} = \frac{[-6x^2 - 12xh - 6h^2 - 2x - 2h + 5] - [-6x^2 - 2x + 5]}{h} ]

Simplify the numerator:

  • Combine like terms: [ f(x+h) - f(x) = [-6x^2 - 12xh - 6h^2 - 2x - 2h + 5] - [-6x^2 - 2x + 5] ] =12xh6h22h= -12xh - 6h^2 - 2h

Now, divide the entire expression by hh:

f(x+h)f(x)h=12xh6h22hh\frac{f(x+h) - f(x)}{h} = \frac{-12xh - 6h^2 - 2h}{h}

Factor out hh from the numerator:

12xh6h22hh=12x6h2\frac{-12xh - 6h^2 - 2h}{h} = -12x - 6h - 2

So, the final simplified form of f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} is:

f(x+h)f(x)h=12x6h2\frac{f(x+h) - f(x)}{h} = -12x - 6h - 2


Would you like any further details or have questions?

Here are 5 related questions to expand your understanding:

  1. What is the difference between f(x+h)f(x+h) and f(x)f(x) geometrically?
  2. How does the expression f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} relate to the concept of a derivative?
  3. Can you derive the general formula for the derivative of f(x)=ax2+bx+cf(x) = ax^2 + bx + c?
  4. How would you apply this method to evaluate f(x)f'(x) for more complex functions?
  5. What does the term hh approaching zero signify in calculus?

Tip: The expression f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} is the difference quotient, which is fundamental in finding the derivative of a function.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Functions
Difference Quotient

Formulas

f(x) = ax^2 + bx + c
Difference Quotient: (f(x+h) - f(x)) / h

Theorems

Quadratic Expansion
Difference Quotient

Suitable Grade Level

Grades 9-12