# Stacking Triangles for Fun and Profit - OranLooney.com

Will definitely be referring back to the diagram in this with the two triangles stacked on top of each other and the rectangle around them. Amazing.

One thing you may have noticed about the trigonometric functions sine and cosine is that they seem to have no agreed upon definition. Or rather, different authors choose different definitions as the starting point, mainly based on convenience. This isn’t problematic or even particularly unusual in mathematics - as long as we can derive any of the other forms from any starting point, it makes little theoretical difference which we start from since they’re all equivalent anyway.

www.oranlooney.com/post/angle-addition/