Question Detail
Question
Find dy/dx if y = xtan x.
Correct Answer
Option D is the correct answer.
Detailed Explanation
This problem requires logarithmic differentiation because the variable x appears in both the base and the exponent.1. Take the natural logarithm of both sides: ln y = ln(xtan x) = tan x * ln x.2. Differentiate both sides with respect to x. Use the product rule on the right side:(1/y) dy/dx = (d/dx tan x) * ln x + tan x * (d/dx ln x)(1/y) dy/dx = (sec2 x) * ln x + tan x * (1/x)3. Multiply by y to solve for dy/dx:dy/dx = y * ( (sec2 x) ln x + tan x / x )4. Substitute y = xtan x back into the equation:dy/dx = xtan x * ( (sec2 x) ln x + tan x / x )This matches option D.
Hint
When the variable appears in both the base and the exponent, logarithmic differentiation is the key. Take the natural logarithm of both sides, then differentiate implicitly.