Prove that cos(-z) = cos(z) and sin(-z) = -sin(z) (ILIEKMATHPHYSICS) (cos is even and sine is odd)

[@oraz.]

Nice and quick one

[@lorenzosaudito]

I knew you were gonna make a video about this property ! 😂

[@Reptar0RAWR0]

can you prove sin(x) = x and cos(x) = 1 for small x

[@AntoshaPushkin]

It's the fundamental theorem of engineering

[@sayunder]

It is never an equality, it’s a limit

[@sayunder]

Which can be approximated as 1 for small x, sure, but it is an approximation based on the Taylor series, not an equality