(-pi/4, pi/4) or (-pi,pi), saying that the range is [-pi/2,pi/2], or worse /mathbb{R}\{k*pi/2 for integers k}. With part b, some students were confused about the orientation of the arctan graph, having it tending to pi/2 for large negative x, and -pi/2 for large positive x. For part c, most students were able to state the derivative of arctan(x), since it was given in the formula sheet, but many failed to show a derivation of the result. Nonetheless, the students who were able to do so, did a good job overallI.
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