Math Problem Statement

Find \( \lim_{{h \to 0}} \frac{2(1 + h)^4 - (1 + h)^3 + 2(1 + h)^2 - 3}{h} \)

Solution

To solve this limit problem, let's examine the expression carefully:

limh02(1+h)4(1+h)3+2(1+h)23h\lim_{{h \to 0}} \frac{2(1 + h)^4 - (1 + h)^3 + 2(1 + h)^2 - 3}{h}

We will expand each term in the numerator and simplify before taking the limit.

Step 1: Expanding Each Term

  1. Expand (1+h)4(1 + h)^4: (1+h)4=1+4h+6h2+4h3+h4(1 + h)^4 = 1 + 4h + 6h^2 + 4h^3 + h^4 So, 2(1+h)4=2+8h+12h2+8h3+2h42(1 + h)^4 = 2 + 8h + 12h^2 + 8h^3 + 2h^4.

  2. Expand (1+h)3(1 + h)^3: (1+h)3=1+3h+3h2+h3(1 + h)^3 = 1 + 3h + 3h^2 + h^3 So, (1+h)3=13h3h2h3-(1 + h)^3 = -1 - 3h - 3h^2 - h^3.

  3. Expand (1+h)2(1 + h)^2: (1+h)2=1+2h+h2(1 + h)^2 = 1 + 2h + h^2 So, 2(1+h)2=2+4h+2h22(1 + h)^2 = 2 + 4h + 2h^2.

Step 2: Substitute and Simplify

Now, substitute these expanded forms into the expression:

2(1+h)4(1+h)3+2(1+h)23=(2+8h+12h2+8h3+2h4)(1+3h+3h2+h3)+(2+4h+2h2)32(1 + h)^4 - (1 + h)^3 + 2(1 + h)^2 - 3 = (2 + 8h + 12h^2 + 8h^3 + 2h^4) - (1 + 3h + 3h^2 + h^3) + (2 + 4h + 2h^2) - 3

Combine like terms:

  • Constant terms: 21+23=02 - 1 + 2 - 3 = 0
  • Terms with hh: 8h3h+4h=9h8h - 3h + 4h = 9h
  • Terms with h2h^2: 12h23h2+2h2=11h212h^2 - 3h^2 + 2h^2 = 11h^2
  • Terms with h3h^3: 8h3h3=7h38h^3 - h^3 = 7h^3
  • Terms with h4h^4: 2h42h^4

So the numerator simplifies to: 9h+11h2+7h3+2h49h + 11h^2 + 7h^3 + 2h^4

Step 3: Factor Out hh

9h+11h2+7h3+2h4h=9+11h+7h2+2h3\frac{9h + 11h^2 + 7h^3 + 2h^4}{h} = 9 + 11h + 7h^2 + 2h^3

Step 4: Take the Limit as h0h \to 0

As h0h \to 0, the terms containing hh, h2h^2, and h3h^3 will approach zero, leaving: limh0(9+11h+7h2+2h3)=9\lim_{{h \to 0}} \left(9 + 11h + 7h^2 + 2h^3\right) = 9

Final Answer:

The limit is: 9\boxed{9}

This matches option A.

Would you like further details or have any questions about any of the steps?


Here are 5 related questions:

  1. How do you handle higher powers in limits when hh approaches zero?
  2. What are other methods to simplify expressions involving limits besides expansion?
  3. Why does factoring out hh help in solving limits of this form?
  4. How does L'Hôpital's Rule apply to similar limit problems?
  5. What is the significance of higher-order terms (like h2,h3h^2, h^3) as h0h \to 0?

Tip: When dealing with polynomial expansions in limits, always organize and simplify terms carefully to see what can be canceled or made negligible as the variable approaches zero.

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Math Problem Analysis

Mathematical Concepts

Limits
Algebraic Expansion
Polynomial Simplification

Formulas

Limit definition: \( \lim_{{h \to 0}} \frac{f(x+h) - f(x)}{h} \)
Binomial Expansion

Theorems

Limit Laws

Suitable Grade Level

Grades 11-12