Can you graph sin or cos sideways? - Answers

If I understand you correctly, yes. Normally we write y=sin(x) or y=cos(x), and because we make our x-axis run horizontally and our y-axis run vertically, this gives us a wave running left-to-right. If instead we wrote x=sin(y) or x=cos(y), the waves would run bottom-to-top. However, notice that in the first case, y is a function of x, but in the second case, x is a function of y. If we wished to make x=sin(y) or x=cos(y) into a function of x, we need to restrict the values of y in the domain so that it will pass the vertical line test. These "restricted" functions have a name, namely arcsin and arccos, and they are referred to as the inverse trigonometric functions.