Question Detail
Question
Given f(x,y)=3tanx·log_ey - y²e^(3x), compute f_xx(x,y)
Correct Answer
Option B is the correct answer.
Detailed Explanation
Differentiate f_x=3sec²x lny-3y²e^(3x) again with respect to x: d/dx[3sec²x lny]=3lny·2sec²x tanx=6lny sec²x tanx, and d/dx[-3y²e^(3x)]=-9y²e^(3x). Summing gives 6log_ey sec²x tanx-9y²e^(3x).
Hint
Differentiate f_x once more with respect to x, using d/dx[sec²x]=2sec²x tanx.