find all solutions of the equation in the interval[0,2π)

Question

cos(x +π) - cosx - 1 =0

Answer 1

Step 1 :

The trigonometric equation is and the interval is .

    (Since the function is negative in third quadrant)

The general solution of  is , where is an integer.

The general solution is , where is an integer.

If , then .

If , then

The solutions are and in the interval .

Solution:

The solutions are and in the interval .