Question

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

Answer 1

1) Compute the derivative of the equation. 2) For the derivative function, find out where the slope is 0 (horizontal). 3) Realize that the resulting function (and the original) are periodic.