C-09-Q159mediumsingle_mcqcot90∘=?\cot 90^\circ = ?cot90∘=?a000b111c∞\infty∞dundefinedব্যাখ্যাCotangent equals cosθsinθ\dfrac{\cos\theta}{\sin\theta}sinθcosθ, and at 90∘90^\circ90∘ this is , giving .