Evaluating the Difference Quotient

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SUMMARY

The discussion focuses on evaluating the difference quotient for the function f(x) = x³ at x = 1. The correct formulation is to calculate ((1 + h)³ - 1³) / h without taking the limit as h approaches 0. The simplification yields h² + 3h + 3, which is the accurate answer, contrasting with the initial incorrect derivative approach that led to confusion.

PREREQUISITES
  • Understanding of polynomial functions, specifically cubic functions.
  • Knowledge of the difference quotient concept in calculus.
  • Ability to simplify algebraic expressions.
  • Familiarity with basic derivative concepts.
NEXT STEPS
  • Study the properties of polynomial functions and their derivatives.
  • Learn how to derive and simplify difference quotients for various functions.
  • Explore the concept of limits in calculus, particularly in relation to difference quotients.
  • Practice problems involving the evaluation of difference quotients for different polynomial degrees.
USEFUL FOR

Students learning calculus, particularly those focusing on derivatives and difference quotients, as well as educators seeking to clarify these concepts for their students.

robertmatthew
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Homework Statement


Evaluate the difference quotient of:
f(1+h)-f(1) / h
if f(x)=x3
and simplify your answer.

Homework Equations



The Attempt at a Solution


I took the derivative of x3 to be 3x2 and solved for when x=1 (given from the difference quotient) and got 3, but when I enter the value it's marked incorrect. Not sure what I'm doing wrong, unless I just interpreted the question the wrong way.
 
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robertmatthew said:

Homework Statement


Evaluate the difference quotient of:
f(1+h)-f(1) / h
if f(x)=x3
and simplify your answer.

Homework Equations



The Attempt at a Solution


I took the derivative of x3 to be 3x2 and solved for when x=1 (given from the difference quotient) and got 3, but when I enter the value it's marked incorrect. Not sure what I'm doing wrong, unless I just interpreted the question the wrong way.

Calculate ((1 + h)^3 - 1^3)/h and do not take the limit h \to 0.
 
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Ah, okay. Got h^2+3h+3, entered it and it was correct. Thanks! I'm not sure why I thought it was asking for the limit, guess I'm still a little fuzzy from the summer.
 

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