Consider the rational function

MATHEMATICS · Multi-part · A Level · Mathematics · Differentiation · Differentiation

Problem

Consider the rational function g(x)=x+2x2−9g(x)=\dfrac{x+2}{x^{2}-9}, whose domain is all real numbers except x=±3x=\pm 3. (a) Compute g′(x)g'(x) and simplify completely. (b) Determine all xx–values in the domain of gg at which g′(x)=0g'(x)=0. State each value exactly. (c) Using the values from part (b) together with the vertical asymptotes, indicate every open interval contained in the domain of gg and decide on which of those intervals gg is increasing or decreasing. Show algebraic reasoning to support each conclusion. (d) Identify the xx–coordinate of every relative extremum of gg that lies in its domain, and state whether each is a relative maximum or a relative minimum. Justify fully.

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