Question

Find the equation of the tangent line to the curve g(X)= 2cos(2X)/(3X) at the point x= pi/3

Answer 1

Evaluate g(π/3)=-1/π (check!)
Therefore the tangent passes through the point P1=(x1,y1)=(π/3,-1/π).
Find the derivative g'(x), and hence the slope at P1.
The tangent line is given by
L1: y-y1 = m(x-x1)
where m=g'(π/3), and (x1,y1) are the coordinates of P1 given above.
If you need help finding g'(x), please post.