Question

What is the derivative of `pi / (9x)^2`?

Answer 1

`d/dx pi/(9x)^2 = (-2pi)/(81x^3)`

Explanation:

`d/dx pi/(9x)^2 = d/dx pi/(81x^2)`
`" " = pi/81 d/dx 1/x^2`
`" " = pi/81 d/dx x^(-2)`
`" " = pi/81 (-2) x^(-2-1)`
`" " = (-2pi)/81 x^(-3)`
`" " = (-2pi)/(81x^3)`