"in the fast changing" is correct and usable in written English.
For example, you could use it in a sentence such as: "Companies must be prepared to adjust their strategies quickly to keep up with the fast changing business landscape."
We believe that the strengths and value of the company's established networks and brands, in the fast changing delivery world, are underappreciated.
In the fast changing world of Internet commerce, it seems name is everything.
It also provides an impetus for managing manufacturing operations from a capability-based perspective in the fast changing knowledge era.
In the fast changing Internet economy, it seems the only certainty is that if you have a smart idea, expect someone to duplicate it in less than a month.
In the fast changing fashion trends, all are now motivated to practice sustainability in design and production throughout the textiles like the use of organic fibers and environmentally safe dyes and chemicals (Gam & Banning 2011).
To meet various customer needs and to adapt rapid changes in the market, firms have to capitalize not only on internal expertise but also on all other available means, such as external knowledge and the convergence or integration of technology, in order to survive in the fast changing market [2, 4, 5].
In addition, the fast changing phasor makes precise measurement more difficult.
It is an expected outcome in the IT industry, because of the fast changing environment.
Using exponentially increasing bin sizes filters out statistical fluctuations in the tail and also resolves the fast changing avalanche peak.
The fast changing events in the Middle East have brought the Palestinians to a cross road of history.
The current strategy of targeting remission or low-disease activity results in the faster changing of DMARDs and so shortening of times on any particular treatment.
