Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

If y = e2x log(x+6), find dy/dx. (Assume log denotes natural logarithm).
Options
A dy/dx = e<sup>2x</sup> (1/(x+6) + 2log(x+6))
Correct Answer
B dy/dx = e<sup>2x</sup> (1/(x+6) - 2log(x+6))
C dy/dx = e<sup>-2x</sup> (1/(x+6) + 2log(x+6))
D dy/dx = e<sup>-2x</sup> (-1/(x+6) - 2log(x+6))
Correct Answer

Option A is the correct answer.

Detailed Explanation

This problem requires the product rule: d/dx(uv) = u'v + uv'.Let u = e2x and v = log(x+6) (assuming natural log, ln(x+6)).Then u' = d/dx(e2x) = 2e2x.And v' = d/dx(ln(x+6)) = 1/(x+6).So, dy/dx = (2e2x)ln(x+6) + e2x(1/(x+6)).Factor out e2x: dy/dx = e2x (2ln(x+6) + 1/(x+6)).Rearranging the terms inside the parenthesis gives e2x (1/(x+6) + 2log(x+6)), which matches option A.

Hint

Apply the product rule for differentiation and remember that d/dx(ln(u)) = u'/u.

Question Info