For what values of x does the graph of f have a horizontal tangent? (Use n as your integer variable. Enter your answers as a comma-separated list.) f(x) = x − 2 sin(x)

Answer 1

f(x) = x - 2sinx

Horizontal tangent when f'(x) = 0.

So, 1 - 2cosx = 0

cosx = 1/2

x = π/3 + 2nπ or 5π/3 + 2nπ, where n = 0, ±1, ±2, ...