Question:medium

If $ f(x) = x^2 + 3x $, then $ f'(x) $ is:

Show Hint

Key Fact: \( \frac{d}{dx}(x^n) = nx^{n-1} \), and \( \frac{d}{dx}(kx) = k \)
Updated On: Nov 26, 2025
  • \( x + 3 \)
  • \( 2x + 3 \)
  • \( x^2 + 3 \)
  • \( 2x \)
Hide Solution

The Correct Option is B

Solution and Explanation

To determine the derivative of the function \( f(x) = x^2 + 3x \), the power rule of differentiation is applied. The power rule is stated as:
\(\frac{d}{dx}[x^n] = nx^{n-1}\)

Applying the power rule to each component of \( f(x) \):

1. For the term \(x^2\):
\(\frac{d}{dx}[x^2] = 2x^{2-1} = 2x\)
2. For the term \(3x\):
\(\frac{d}{dx}[3x] = 3\)

Consequently, the derivative \( f'(x) \) is found by differentiating each term and summing the results:

\(f'(x) = 2x + 3\)

Therefore, the derivative is \(2x + 3\).

Was this answer helpful?
1