Question

Find an equation of the tangent line to the curve at the given point. y = x + tan(x) at (pi, pi)

Answer 1

Differentiating :

y' = 1 + sec^2(x),

cosπ=−1

plug in pi = -1 ,for x:

1 + sec^2(pi) = 1 +  (-1)^2 
                      = 2