High School

Find \( f'(x) \) if \( f(x) = 3x^5(x^4 - 3) \).

A. \( f'(x) = 45x^8 - 108x^5 \)
B. \( f'(x) = 45x^8 - 15x^5 \)
C. \( f'(x) = 45x^9 - 108x^5 \)
D. \( f'(x) = 45x^9 - 15x^5 \)

Answer :

Final answer:

After differentiating the given function f(x) = 3x^5(x^4 - 3), it is determined that none of the provided multiple-choice options match the correct derivative, which is 27x^8 - 45x^5. Since the correct answer is not listed, the student should re-evaluate the options or the derivation process.

None of the option is correct.

Explanation:

The student has asked us to find f^x when the function f(x) = 3x^5(x^4 - 3). To find f^x, we need to differentiate the function f(x) with respect to x.

Let's derive the given function step by step:

Apply the power rule for differentiation to the term 3x^5, which becomes 15x^4.

Then differentiate the polynomial (x^4 - 3), which results in 4x^3.

Now, follow the product rule: the derivative of two multiplied functions u and v (where u = 3x^5 and v = x^4 - 3) is u'v + uv'.

Substitute the differentiated parts into the product rule formula: (15x^4)(x^4 - 3) + (3x^5)(4x^3).

Simplify the expression: 15x^8 - 45x^5 + 12x^8.

Combine like terms: (15x^8 + 12x^8) - 45x^5, which simplifies to 27x^8 - 45x^5.

None of the options (a), (b), (c), or (d) match 27x^8 - 45x^5, which suggests there might be an error either in the student's provided options or my calculation. Hence, I must refrain from choosing any of the provided answers and advise re-evaluating the work.

None of the option is correct.