y = 2 ^ x
take ln of both sides
ln( y) = ln (2 ^ x)
using the log rules we can bring the power of x down in front of the ln
ln( y ) = x*ln(2)
differentiate both sides wrt x
( 1 / y ) * dy / dx = ln(2)
dy / dx = y*ln(2) ==> rememer y = 2 ^ x
dy / dx = ln(2) * 2 ^ x