in a nutshell, sine, cosine and tangent are trigonometric functions (do you know what a function is?). they are functions of angles and their input values are called arguments. see here
When we press any of these buttons on any scientific calculator and press enter, we are given a number. As we do this again the number changes. What does it mean exactly? When I first did tried this I thought sine was sort of a bit like pi, but since the number changes it is obviously different. Just to clarify, do these numbers signify points on some sort of continuous curve? Or is it something different?
Please excuse my ignorance.