Question

Find the equation of the tangent line to the curve y = 2 x cos x at the point ( pi , -2 \pi).
The equation of this tangent line can be written in the form y = mx+b where




m =
b =

Answer 1

y = 2 x cos x
y' = 2cos x - 2x sinx
y'(π) = 2cosπ - 2π sinπ = -2
y + 2π = -2 (x - π)
y = -2x

Answer 2

where's m and b?