A graph of a functions is a visual representation of the pairs (input, output), in the plane. This applet will help you to understand the connection between the graph of a function and a function as ...

The cosine (cos) function takes the angle Ɵ and gives the answer to adjacent ÷ hypotenuse (in this example, 16/32). cos⁻¹ is the inverse function of cos.

National 5; Working with the graphs of trigonometric functions Example. Trigonometric graphs can be sketched when you know the amplitude, period, phase and maximum and minimum turning points.

Part of that is the way it's taught. Students are taught the "unit circle" and its relationship to trigonometry, but many fail to make the leap on how crucial circles are for trig functions.