calculus
posted by Robyn .
5) Find the points on the curve below at which the tangent is horizontal. Use n as an arbitrary integer. (Select all that apply.)
y=Sin(x) / 2+ Cos (x)

y' = cosx/2  sinx
y'=0 where cosx = 2sinx
That is, where tanx = 1/2
So, if t = arctan(1/2) the tangent line is horizontal at
x = t + nπ