Find the domain of 
Definitions:
United States
A country in North America, comprising 50 states, a federal district, five major self-governing territories, and various possessions.
Germany
A country in Central Europe, known for its rich history, culture, and significant contributions to the fields of science, technology, and economy.
Import Substitution
An economic strategy aimed at reducing foreign dependency by local production of industrialized products.
Local Industries
Economic activities or sectors focused on producing goods or services predominantly catered to the domestic or regional market.
Q18: Let <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB6988/.jpg" alt="Let ;
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Q62: Use the total differential to approximate the
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