Math Problem Statement

Evaluate the limit, if it exists. (If an answer does not exist, enter DNE.) lim x→0 x6 cos

7 x

Solution

We are tasked with evaluating the following limit:

limx0x6cos(7x)\lim_{x \to 0} x^6 \cos(7x)

Step-by-step solution:

  1. Examine the behavior of the cosine function: cos(7x)\cos(7x) The cosine function is continuous everywhere, and specifically, at x=0x = 0, we have: cos(70)=cos(0)=1\cos(7 \cdot 0) = \cos(0) = 1

  2. Simplifying the expression: We now rewrite the limit, knowing that cos(7x)\cos(7x) approaches 1 as x0x \to 0: limx0x6cos(7x)=limx0x61=limx0x6\lim_{x \to 0} x^6 \cos(7x) = \lim_{x \to 0} x^6 \cdot 1 = \lim_{x \to 0} x^6

  3. Evaluate the limit of x6x^6 as x0x \to 0: The function x6x^6 approaches 0 as xx approaches 0: limx0x6=0\lim_{x \to 0} x^6 = 0

Therefore, the limit is:

0\boxed{0}

Would you like any more details or clarifications?


Here are 5 related questions you might find interesting:

  1. How do you find the limit of a product involving trigonometric functions?
  2. What is the limit of x2sin(x)x^2 \sin(x) as x0x \to 0?
  3. How does L'Hôpital's Rule apply to limits involving indeterminate forms?
  4. What happens when you take the limit of higher powers of xx, like x8x^8, as x0x \to 0?
  5. Can you explain how continuity helps in simplifying limits?

Tip: When dealing with limits, always check if the trigonometric functions can be simplified near 0 by using known values or approximations (like cos(0)=1\cos(0) = 1 or sin(0)=0\sin(0) = 0).

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Trigonometric Functions

Formulas

lim x→0 x^6 cos(7x)
cos(0) = 1

Theorems

Continuity of trigonometric functions
Basic limit properties

Suitable Grade Level

Grades 11-12 (Advanced High School Calculus)