Consider the functions and

MATHEMATICS · Subjective · AP · Calculus AB · Limits and Continuity · Limits and Continuity

Problem

Consider the functions f(x)=3+7x4f(x)=3+\dfrac{7}{x^{4}} and g(x)=(3+7x4)(−2+1x2)g(x)=\bigl(3+\dfrac{7}{x^{4}}\bigr)\bigl(-2+\dfrac{1}{x^{2}}\bigr). (i) Explain, without performing detailed numerical calculation, why lim⁡x→∞f(x)=3\displaystyle \lim_{x\to\infty}f(x)=3. (ii) Using similar reasoning, determine lim⁡x→∞g(x)\displaystyle \lim_{x\to\infty}g(x) and state the property of limits that justifies every step of your explanation.

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