Math Problem Statement

If f(x) = ln(3x^2 + x), find f'(1).

Solution

The given problem asks:

"If f(x)=ln(3x2+x)f(x) = \ln(3x^2 + x), find f(1)f'(1)."

Let’s solve it step-by-step.


Step 1: Differentiate f(x)=ln(3x2+x)f(x) = \ln(3x^2 + x) using the chain rule.

The chain rule states: ddx[ln(u)]=1ududx\frac{d}{dx}[\ln(u)] = \frac{1}{u} \cdot \frac{du}{dx} Here, u=3x2+xu = 3x^2 + x. So, first, differentiate uu with respect to xx.

dudx=ddx(3x2+x)=6x+1\frac{du}{dx} = \frac{d}{dx}(3x^2 + x) = 6x + 1

Now apply the chain rule to find f(x)f'(x):

f(x)=13x2+x(6x+1)f'(x) = \frac{1}{3x^2 + x} \cdot (6x + 1)


Step 2: Evaluate f(x)f'(x) at x=1x = 1.

Substitute x=1x = 1 into the derivative expression:

f(1)=6(1)+13(1)2+1=6+13+1=74f'(1) = \frac{6(1) + 1}{3(1)^2 + 1} = \frac{6 + 1}{3 + 1} = \frac{7}{4}


Final Answer:

f(1)=74f'(1) = \frac{7}{4}


Would you like further details, or do you have other questions?


Here are five related questions:

  1. How does the chain rule work in more complex functions like ln(sin(x2))\ln(\sin(x^2))?
  2. What is the significance of evaluating a derivative at a specific point?
  3. How would the derivative change if the argument inside the logarithm was 3x2+x+13x^2 + x + 1?
  4. What are the domain restrictions for the function f(x)=ln(3x2+x)f(x) = \ln(3x^2 + x)?
  5. Can you apply implicit differentiation to logarithmic functions?

Tip: Always ensure the argument of a logarithmic function is positive to avoid undefined values.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Logarithmic Functions

Formulas

Chain rule: d/dx [ln(u)] = 1/u * du/dx
Power rule for differentiation: d/dx [x^n] = n * x^(n-1)

Theorems

Chain Rule
Derivative of Logarithmic Functions

Suitable Grade Level

Undergraduate Level (Calculus I)