A cell phone charger operates at 5 volts and can deliver a maximum current of 1.0 Amp. If your cell phone has an energy storage capacity of 33.0~\text{kiloJoules}33.0 kiloJoules, what is the shortest possible time (in hours) it would take to fully charge your empty phone battery using this charger

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

we have been given a quadratic function and we need to restrict the domain such that it becomes a one to one function.

we know that vertex of this quadratic function occurs at (5,2).

further, we know that range of this function is .

if we restrict the domain of this function to either or , it will become one to one function.

let us know find its inverse.

upon interchanging x and y, we get:

let us now solve this function for y.

hence, the inverse function would be if we restrict the domain of original function to and the inverse function would be if we restrict the domain to .