Let g(x)= (2x)- (x) x(2 x-1) for all for which the denominator is non-zero.

MATHEMATICS · Multi-part · CBSE · Mathematics · Continuity and Differentiability · Continuity and Differentiability

Problem

Let g(x)=sin⁡(2x)−sin⁡(x)x(2cos⁡x−1)g(x)=\frac{\sin(2x)-\sin(x)}{x(2\cos x-1)} for all x≠0x\neq 0 for which the denominator is non-zero. (a) Determine all real numbers in the interval (−π,π)(-\pi,\pi) where gg is not defined. Give reasons that cite both the numerator and denominator. (b) Evaluate lim⁡x→0g(x)\displaystyle \lim_{x\to 0} g(x), providing a complete limit argument that may involve trigonometric identities and standard limits. (c) State the type of discontinuity that occurs at x=0x=0 and justify your classification. (d) Define a new function hh by assigning an appropriate value at x=0x=0 so that hh becomes continuous at x=0x=0. Prove that your definition achieves continuity. (e) Without graphing technology, describe the local behavior of gg near x=0x=0 and explain how this behavior is consistent with your work above.

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