In this problem it says it uses the solutions in the interval to solve trigonometric equation but how do you determine those solutions?

bjective 4: Solve Trigonometric Equations xample 2: Solving Trigonometric Equations olve the following equations. . 2cosx-1=0 olution: a. First solve for cos x ; COS X= 2 cos x is positive on the I and IV quadrants, and COS 3 N Therefore, the reference angle is ~ and there are Figure 2.35a w TE STT two solutions in the interval [0, 2x], x = - and x = 2x - 3 3 We can obtain the general solution by adding integer multiples of 27 . Therefore the general solution are TE 5 TT + 2nat and x = + 2n where n is an integer. X = 3 3