# Intro - Earthquakes and Trigonometry It's natural to wish for the sky to fall, or for the earth to crack open and swallow you whole. However, when this actually happens you might be thinking otherwise. Earthquakes are tremors in the ground caused by releases of pressure deep underground. This leads to a cascade failure where a shock wave is sent travelling through the ground towards us. You might've seen videos of cars, buses, roads, buildings undulating as the security camera shakes violently and everything goes out of focus. ![[Pasted image 20231007115250.png]] It might not be obvious when your house is under threat of collapse, but this is actually an example of a sinusoidal wave - the undulating up-and-down movements of the ground exemplify this! Heck, we can even model the earthquake by taking the height of this up-and-down movement, which will give us a graph like this: ![[Pasted image 20231007115723.png]] This ties in nicely with the overarching theme here - sinusoidals! Let's dive into them before we get lost! # The Basics - Sines, Cosines, Tangents From the moment you're thrust into this soulless earth, you're subject to constant droning about what seems to be three mystical icons - "sine", "cosine", "tangent". # "Uh-Oh" - Cot, Cosec, Sec # EXTENDED - Sinh, Cosh, Tanh - "The Rabbit Hole" # Example Questions # What's Next? $$