How can I find this answer?

Question

Determine the point(s) (if any) at which the graph of the function has a horizontal tangent line.

y = √3 x + 2 cos(x), 0 ≤ x < 2𝜋

Step 1: Find the derivative y'

Step 2: Set y'=0 and solve for x

x1= (smaller x-value)

x2= (larger x-value)

Step 3: Find the y values

Answer 1

y^' = √3 - 2sinx = 0

sinx = √3/2

x = π/3 or 2π/3