The three steps:
Find the derivative of the function (in this case use the product rule)
Find the value of the function and derivative for yo and y'=m
Put in the values into the point-slope form of the equation for the line.
y = sin x cos x
y'= cos x cos x + sin x(-sin x) = cos2 x - sin2 x
y(π/6) = sin (π/6) cos (π/6) = (1/2)(√3/2)=√3/4
y'(π/6) = cos2 (π/6) - sin2 (π/6) = (√3/2)2-(1/2)2 = 3/4 -1/4 =1/2
Thus the equation of the line is y - √3/4 = 1/2 (x-(π/6))