Calculus: Derivative of ln Functions

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the derivative of the function $y = rac{1}{x^2}$ using the natural logarithm differentiation rule?

  • $ rac{1}{x^2}$
  • $ rac{-2}{x^4}$
  • $- rac{2}{x^3}$ (correct)
  • $- rac{1}{2x^2}$

Which of the following is a correct application of the chain rule when deriving $y = ext{ln}(u)$ with $u = ext{sin}(x)$?

  • $dy/dx = rac{ ext{cos}(x)}{ ext{sin}(x)}$
  • $dy/dx = rac{- ext{cos}(x)}{u^2}$
  • $dy/dx = rac{1}{ ext{sin}(x)}$
  • $dy/dx = rac{1}{u} rac{du}{dx}$ (correct)

Given the function $y = ext{ln}(x^2 + 1)$, what is the derivative $dy/dx$?

  • $ rac{x}{x^2 + 2}$
  • $ rac{1}{x^2 + 1}$
  • $ rac{2x}{x + 1}$
  • $ rac{2x}{x^2 + 1}$ (correct)

What is the expression for $dy/dx$ given that $y = ext{ln}(e^x)$?

<p>$1$ (C)</p> Signup and view all the answers

If $y = ext{ln}( ext{cos}(2x))$, what will be $dy/dx$?

<p>$- rac{2 ext{sin}(2x)}{ ext{cos}(2x)}$ (C)</p> Signup and view all the answers

For the function $y = ext{ln}(5x + 3)$, which statement regarding its derivative is correct?

<p>$dy/dx = rac{5}{5x + 3}$ (A)</p> Signup and view all the answers

What is the outcome of differentiating $y = e^{ ext{tan}(x)}$ using the chain rule?

<p>$e^{ ext{tan}(x)} ext{sec}^2(x)$ (B)</p> Signup and view all the answers

If $y = ext{ln}(x)$, the derivative $dy/dx$ is:

<p>$ rac{1}{x}$ (B)</p> Signup and view all the answers

Flashcards

Derivative of ln(x)

The derivative of the natural logarithm of x is 1/x.

Derivative of ln(f(x))

The derivative of the natural logarithm of a function f(x) is f'(x) / f(x).

Implicit Differentiation

Finding the derivative of a function where the variables are not explicitly solved for one another, instead both sides of the equation are differentiated with respect to x, solving for dy/dx

Chain Rule

A rule for differentiating composite functions (functions within functions).

Signup and view all the flashcards

Natural Logarithm

A logarithm with base e.

Signup and view all the flashcards

Study Notes

Derivative of Natural Logarithmic Functions

  • A natural logarithm function of x is the logarithm of x to base e (ln|x| = logex).
  • x can be rewritten as x = eln x.
  • If y = ln x, then d/dx [ln x] = 1/x
    • Proof:
      • ey = x
      • Differentiating both sides: ey (dy/dx) = 1
      • dy/dx = 1/ey = 1/x
  • Generally, if y = ln[f(x)], then d/dx {ln[f(x)]} = f'(x)/f(x)

Examples of Finding Derivatives

  • Example (i): y = ln(x2)

    • Let u = x2, so y = ln(u)
    • du/dx = 2x, dy/du = 1/u = 1/x2
    • dy/dx = (dy/du) * (du/dx) = (1/x2) * (2x) = 2/x
  • Example (ii): y = ln(cos2x)

    • Let u = cos2x, so y = ln(u)
    • du/dx = -2sin(2x), dy/du = 1/u = 1/cos2x = sec2x
    • dy/dx = (dy/du) * (du/dx) = (sec2x) * (-2sin(2x)) = -2tan(2x)sec(2x)
  • Example (iii): y = ln(√(x2 + 1) / 3√(x3 + 1))

    • This example involves more complex substitutions and chain rule application for finding the derivative.

Implicit Differentiation

  • Example: y2 - 2y√(1 + x2) + x2 = 0
    • Implicitly differentiate both sides with respect to x to find dy/dx.
    • The solution involves carefully applying the chain rule and isolating dy/dx to solve for it.

Other Differentiation Exercises (Implicit Differentiation)

  • Exercises are given for finding dy/dx for various equations involving x and y (e.g., xy3 - 2x2y2 + x4 = 1, x2sin y - y cos x = 10x3, etc.) These problems require applying implicit differentiation techniques. The solutions involve multiple steps based upon the chain rule and implicit differentiation rules.

Exponential Function Differentiation

  • Exercises involve finding derivatives of functions involving exponential functions, trigonometric functions, and logarithms.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

LN 2
30 questions

LN 2

AwedExuberance avatar
AwedExuberance
Natural Logarithm (ln) Function
10 questions
Use Quizgecko on...
Browser
Browser