Study Guide for Derivative Calculation of F(x)

Calculating the Derivative of F(x)

  • Function Definition:
    • Given the function is defined as:
    • F(x) = 3x f'(x) - f(x)
  • Need to Find:
    • Calculate the derivative F'(2).
    • We use the product rule and chain rule to differentiate.

Applying the Product Rule

  • Product Rule Formula:
    • The product rule states that for two functions u(x) and v(x):
    • (u v)' = u'v + uv'
    • For the term 3x f'(x), let:
    • u(x) = 3x and v(x) = f'(x)
  • Derivatives of u and v:
    • Calculate u'(x):
    • u'(x) = 3
    • Calculate v'(x), which is f''(x) by the definition of derivatives:
    • v'(x) = f''(x)

Derivative of F using the Product Rule

  • Applying the Product Rule:
    • The derivative of 3x f'(x) is:
    • (3x f'(x))' = u'v + uv' = (3)(f'(x)) + (3x)(f''(x)) = 3f'(x) + 3x f''(x)
    • The derivative of -f(x) is:
    • (-f(x))' = -f'(x)
    • Therefore, for F(x) = 3x f'(x) - f(x):
    • F'(x) = (3f'(x) + 3x f''(x)) - f'(x)
    • F'(x) = 2f'(x) + 3x f''(x)
  • Evaluating F'(2):
    • Substitute x = 2, f'(2) = -4, and f''(2) = 1 into our derivative equation:
    • Calculation steps:
    • F'(2) = 2f'(2) + 3(2)f''(2)
    • F'(2) = 2(-4) + 6(1)
    • F'(2) = -8 + 6
    • F'(2) = -2

Conclusion

  • Thus, the answer to the problem is:
    • **F