A function is defined on the open interval and is known to be continuous on that interval

MATHEMATICS · Multi-part · AP · Calculus AB · Limits and Continuity · Limits and Continuity

Problem

A function qq is defined on the open interval (0,3)(0,3) and is known to be continuous on that interval. The following function values are given: q(0.2)=4q(0.2)=4, q(2)=−1q(2)=-1, and q(2.9)=5q(2.9)=5. No information is provided about any values of qq at x=0x=0 or x=3x=3. (1) Prove that there exists at least one number cc in (0.2,2)(0.2,2) such that q(c)=0q(c)=0. Present your argument in a logically ordered sequence of statements. (2) Discuss whether the existence of a number cc in (2,2.9)(2,2.9) with q(c)=0q(c)=0 can be guaranteed from the information provided. Give a reasoned explanation, clearly indicating any additional information that would be necessary to reach a definitive conclusion. (3) Explain how extending the domain of qq to include the endpoints x=0x=0 and x=3x=3 could affect the conclusions in parts (a) and (b). Be explicit about which new data points would be required and why.

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