Question

What is the derivative of `pi(x)`?

Answer 1

`pi`

Explanation:

Don't let the symbol `pi` confuse you. Remember that `pi` is just a number, roughly equivalent to `3.14`. If it helps, replace `pi` with `3.14`, to remind you that you're really taking the derivative of `3.14x`.

Recall that the derivative of a constant times `x` is the constant; this is because something like `pix` is a linear equation with constant slope. And since derivative is slope, a linear equation has a constant (i.e. numerical) derivative.

You can also find the result using the power rule:
`d/dxpix^1`
`=1*pix^(1-1)`
`=pix^0`
`=pi->` any number (except 0) to the zero power is `1`

Answer 2

`pi' (x)`

Explanation:

unless `pi(x)` is a function in which case, hilarious

and, well, ...

`d/dx pi(x) = pi' (x) = d/dx pi(x)`