In real world situations we often discuss the angle of elevation and depression. The angle of elevation and depression is used often in word problems, especially those involving a persons line of sight as they look up at an object. These angles can be used to solve problems involving trigonometric functions such as sine, cosine, and tangent, and the inverse trigonometric functions.
We can apply trigonometry to problems that involve angles of elevation and angles of depression. So here we have an angle of elevation if we think about a boat on the water looking at the very top of a lighthouse. So if we said that the water level was our zero then the angle that this boat would have to look up see the very top of that lighthouse would be theta or our angle of elevation how high up they had to look. If we talk about angle of depression, so if we move over here and if we write angle of depression. So now this has nothing too do with how this guys feels, he's actually a stunt devil and he's about to jump off a building onto this little foam matters. So what he's going to do is from his eye sight or if we said that, that is level to where he wants to land which is the center of that foam mat, so if I draw in a line there that angle between the horizontal and the angle of where he wants to land would be theta our angle of depression. So keep that I mind draw pictures whenever you have a word problem that uses angle of elevation and angle of depression.