AJ L. answered 05/08/23
Patient and knowledgeable Calculus Tutor committed to student mastery
y = e-2xcos(6x)
dy/dx = (e-2x)'cos(6x) + e-2xcos(6x)' <-- Product Rule
dy/dx = -2e-2xcos(6x) - 6e-2xsin(6x)
y = -9sin2(x)/cos(x)
y = -9sin(x)[sin(x)/cos(x)]
y = -9sin(x)tan(x) <-- Simplified
dy/dx = -9cos(x)tan(x) + [-9sin(x)sec2(x)] <-- Product Rule
dy/dx = -9sin(x) - 9tan(x)sec(x)
Hope this helped!