Does the inequality change in this equation involving trigonometric identity, when I am solving for the angel?
By graphing this inequality it becomes clear that you must limit the question to a valid range. The the graph shows that the continuous range to use is -pi/2 to + pi/2, (-90 degrees to + 90 degrees). this being accepted, it is clear that values of theta from approx -58 degrees thru +58 degrees satisfy the inequality. Armed with this data you want to express this inequality in terms of the angle theta something like; -58 degrees <= theta <= +58 degrees (within the range -90 to +90).
