Q. Determine the following limit in simplest form. If the limit is infinite, state that the limit does not exist (DNE).x→∞lim3+x+x2−19x3+36x4Answer:
Analyze Behavior of Functions: To find the limit of the function as x approaches infinity, we need to analyze the behavior of the numerator and the denominator separately. We will start by simplifying the function, focusing on the highest power of x in both the numerator and the denominator.
Simplify Numerator: In the numerator, we have a square root of a polynomial. The highest power of x inside the square root is x4, so we can factor out x2 from the square root to simplify the expression.−19x3+36x4=x2⋅−x19+36
Focus on Denominator: In the denominator, the highest power of x is x2. As x approaches infinity, the lower powers of x (3 and x) become insignificant compared to x2. Therefore, we can focus on x2 in the denominator.3+x+x2≈x2
Rewrite Original Function: Now we rewrite the original function, focusing on the dominant terms: 3+x+x2−19x3+36x4≈x2x2−x19+36
Simplify x2 Terms: We can now simplify the x2 terms in the numerator and the denominator: x2x2−x19+36≈−x19+36
Further Simplification: As x approaches infinity, the term −x19 approaches 0, so we can simplify the expression inside the square root further: −x19+36≈36
Final Limit Calculation: The square root of 36 is 6, so the limit of the function as x approaches infinity is 6.
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