
RAFAH A. answered 03/16/21
Former College Instructor, Calculus and Algebra Tutor
The slope of the tangent is the first derivative of the the function,
f (x) =3 sec 2 (x)
f ' (x) = 3* 2* sec (x) * sec(x) tan(x)
= 6 sec2 (x) tan(x)
at x = 11pi/6
f ' (x) = 6 sec2 (11pi/6) tan(11pi/6)
= - 4.6
To write the equation of the line we need to know the slope and a point in the line,
for x1= 11pi/6 , y1 = 3 sec 2 (x) = 3 sec 2 (11pi/6) = 4
y - y1 = m ( x - x1 )
y - 4 = -4.6 ( x - 11pi/6 )