Math Problem Statement

Let f(x) be the function 5x^2 - 6x + 5. Then the quotient (f(5+h) - f(5)) / h can be simplified to ah + b. Find a and b.

Solution

We are given the function f(x)=5x26x+5f(x) = 5x^2 - 6x + 5, and the problem asks us to simplify the expression for the difference quotient:

f(5+h)f(5)h\frac{f(5+h) - f(5)}{h}

We are also asked to express the result as ah+bah + b, and find the values of aa and bb.

Step-by-Step Solution:

  1. Substitute f(5+h)f(5+h) into the function: f(5+h)=5(5+h)26(5+h)+5f(5+h) = 5(5+h)^2 - 6(5+h) + 5 Expand each part: =5((5+h)2)6(5+h)+5= 5((5+h)^2) - 6(5+h) + 5 =5(25+10h+h2)6(5+h)+5= 5(25 + 10h + h^2) - 6(5 + h) + 5 =5(25)+5(10h)+5(h2)6(5)6h+5= 5(25) + 5(10h) + 5(h^2) - 6(5) - 6h + 5 =125+50h+5h2306h+5= 125 + 50h + 5h^2 - 30 - 6h + 5 =100+50h+5h26h= 100 + 50h + 5h^2 - 6h =100+44h+5h2= 100 + 44h + 5h^2

  2. Calculate f(5)f(5): f(5)=5(52)6(5)+5f(5) = 5(5^2) - 6(5) + 5 =5(25)30+5= 5(25) - 30 + 5 =12530+5=100= 125 - 30 + 5 = 100

  3. Form the difference f(5+h)f(5)f(5+h) - f(5): f(5+h)f(5)=(100+44h+5h2)100f(5+h) - f(5) = (100 + 44h + 5h^2) - 100 =44h+5h2= 44h + 5h^2

  4. Simplify the difference quotient: f(5+h)f(5)h=44h+5h2h\frac{f(5+h) - f(5)}{h} = \frac{44h + 5h^2}{h} Factor out hh: =h(44+5h)/h= h(44 + 5h) / h Cancel hh: =44+5h= 44 + 5h

Thus, the simplified form is 44+5h44 + 5h. In the form ah+bah + b, we have:

a=5,b=44a = 5, \quad b = 44

Final Answer:

a=5,b=44a = 5, \quad b = 44

Would you like further details or have any questions?

Related Questions:

  1. How do you find the derivative of a quadratic function like f(x)=5x26x+5f(x) = 5x^2 - 6x + 5?
  2. What is the meaning of the difference quotient in calculus?
  3. How can you determine the slope of a tangent line using the limit definition of the derivative?
  4. How does expanding binomials, like (5+h)2(5+h)^2, help in calculus problems?
  5. What happens to the difference quotient as hh approaches 0?

Tip: Always simplify terms before applying the difference quotient formula—it helps prevent mistakes in algebraic manipulation.

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Math Problem Analysis

Mathematical Concepts

Algebra
Difference Quotient
Quadratic Functions
Derivative Approximation

Formulas

f(x) = ax^2 + bx + c
Difference quotient: (f(5+h) - f(5)) / h
Binomial Expansion: (a + b)^2 = a^2 + 2ab + b^2

Theorems

Derivative Definition using Difference Quotient

Suitable Grade Level

Grades 10-12