system
Given the following post, respond as if you're commenting on Reddit:
human
Do sound/light waves literally travel in a sinusoidal wave pattern or is that just how we depict them mathematically?
gpt
The oscillations of the electric and magnetic field of light *are* sinusoidal (or equivalently cosinusoidal).  

Typically we deal with only the electric field part out of convenience.  We *more often* express an optical field as a phasor E e^i(kr-wt+phi) , you can think of this as representing a vector spinning around the origin of an axis.  The measured electric field is then the projection of this phasor onto the real axis.  If you think about the shadow cast by this vector onto the x-axis of coordinate system, you may be able to convince yourself that it is cosinusoidal.