The phrase "a first task" is correct and usable in written English.
It can be used when introducing or referring to the initial assignment or duty in a sequence of tasks.
Example: "Before we begin the project, let's outline a first task that everyone can contribute to."
Alternatives: "an initial task" or "a primary task".
A first task would be to raise the house, dig a basement and reseat the house on a new foundation.
A first task, once talks do get going, will be to convince North Korea of how grave a miscalculation that would be.
Applications presented here involves each a first task T1 which has a periodicity of 40 ms, each time execution of this task finish, the remaining sequence begin (creation of task T2 ) and a new instance of T1 is ran.
This kind of case can be found on some computer vision algorithm where a first task is detecting objects and then a particular treatment is being applied on each detected object.
As a first task, several important building features are compiled, such as campus location, year of construction, energy generation systems for each building, gross floor area, and occupancy estimates per building.
As a first task, we analyze the frequency content of the projected fringes in the Fresnel diffraction zone for parallel and divergent light illumination at different grating parameters and wavelengths.
But H.E.W. officials commissioned Mr. Newman to lead a second task force on reform in 1971.
A second task force was being assembled to go to Tanzania.
R. Key Dismukes, an aviation researcher at the NASA Ames Research Center, said concentrating on two tasks at once created a third task: balancing between the first two tasks.
In a second task, Black races to blow out a candle with a stocking covering his head.
In a second task, animals sat before a square tray and looked for a piece of food set in any one of the four corners.
