Question

What does tan 0 equal?

Answer 1

`tan(0)` is "undefined"

Explanation:

In general based on a triangle with adjacent side on the X-axis and a hypotenuse extending from the origin to a point on the unit circle `tan` is defined as
`color(white)("XXX")tan(theta) = ("opposite side")/("adjacent side")`

As `theta rarr 0`
the `"adjacent side" rarr 0`
so the definition of `tan(0)` becomes an attempt to divide by `0`,
an operation which is "undefined"