2021 THREE(a)

Achievement
Question
Differentiate y=cotxx2+1y = \dfrac{\cot x}{x^2 + 1}.

You do not need to simplify your answer.
Official Answer
dydx=(x2+1)(cosec2x)(cotx)(2x)(x2+1)2\dfrac{dy}{dx}=\dfrac{(x^2+1)(-\cosec^2 x)-(\cot x)(2x)}{(x^2+1)^2}
Grading Criteria

Achievement (u)

  • Correct derivative.

Merit (r)

-

Excellence T1

-

Excellence T2

-
Video Explanation
NCEA Level 3 Calculus Differentiation 2021 NZQA Exam - Worked Answers by infinityplusone(starts at 56:14)
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