Math Problem Statement

Given the function f, of, x, equals, minus, start fraction, 3, divided by, 2, x, end fraction, minus, start fraction, 5, divided by, 6, x, squared, end fraction, commaf(x)=−2x3​−6x25​, find f, prime, of, 2, .f′(2). Express your answer as a single fraction in simplest form.

Solution

To find f(2)f'(2), we first need to determine the derivative of the given function f(x)f(x).

The function is given as:

f(x)=32x56x2f(x) = -\frac{3}{2}x - \frac{5}{6}x^2

Step 1: Differentiate f(x)f(x)

We will differentiate term by term.

  • The derivative of 32x-\frac{3}{2}x is simply 32-\frac{3}{2}.
  • The derivative of 56x2-\frac{5}{6}x^2 (using the power rule, where ddxxn=nxn1\frac{d}{dx}x^n = nx^{n-1}) is:

ddx(56x2)=56×2x=53x\frac{d}{dx} \left( -\frac{5}{6}x^2 \right) = -\frac{5}{6} \times 2x = -\frac{5}{3}x

So, the derivative f(x)f'(x) is:

f(x)=3253xf'(x) = -\frac{3}{2} - \frac{5}{3}x

Step 2: Find f(2)f'(2)

Now, substitute x=2x = 2 into the derivative:

f(2)=3253(2)f'(2) = -\frac{3}{2} - \frac{5}{3}(2)

Simplify the expression:

f(2)=32103f'(2) = -\frac{3}{2} - \frac{10}{3}

Step 3: Combine the fractions

To combine 32-\frac{3}{2} and 103-\frac{10}{3}, we need a common denominator. The least common denominator between 2 and 3 is 6.

Convert the fractions:

32=96,103=206-\frac{3}{2} = -\frac{9}{6}, \quad -\frac{10}{3} = -\frac{20}{6}

Now add the two fractions:

f(2)=96206=296f'(2) = -\frac{9}{6} - \frac{20}{6} = -\frac{29}{6}

Final Answer:

f(2)=296f'(2) = -\frac{29}{6}

This is the value of f(2)f'(2) expressed as a single fraction in simplest form.

Would you like further details on the derivative process or the simplification steps?


Here are five related questions you might find useful:

  1. How do you find the derivative of a function with multiple terms?
  2. What is the power rule for differentiation?
  3. Can you differentiate a polynomial of higher degree?
  4. How do you find critical points using derivatives?
  5. What is the significance of a derivative at a specific point?

Tip: When combining fractions with different denominators, always find the least common denominator to simplify calculations efficiently.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Algebra

Formulas

Power rule for differentiation: d/dx(x^n) = nx^(n-1)
Derivative of a linear term: d/dx(ax) = a
Derivative of a quadratic term: d/dx(ax^2) = 2ax

Theorems

Power Rule

Suitable Grade Level

Grades 11-12