Question

Find the equation of the tangent line to the graph of f(a) = sec(a) at the point (0, 1).

Answer 1

Let the required equation be y = mx + c; where y = 1, m = f'(0), x = 0
f(a) = sec(a)
f'(a) = sec(a)tan(a)
f'(0) = sec(0)tan(0) = 0

y = mx + c
1 = 0(0) + c
c = 1

Therefore, required equation is
y = 1.