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find the exact value of \\(\\sin(\\tan^{-1}(-2))\\)\\(\\bigcirc\\ -\\df…

Question

find the exact value of \\(\sin(\tan^{-1}(-2))\\)\\(\bigcirc\\ -\dfrac{1}{2}\\)\\(\bigcirc\\ -\dfrac{2}{\sqrt{5}}\\)\\(\bigcirc\\ \dfrac{2}{\sqrt{5}}\\)\\(\bigcirc\\ \dfrac{1}{\sqrt{5}}\\)\\(\bigcirc\\ -\dfrac{1}{\sqrt{5}}\\)

Explanation:

Step1: Let \( \theta = \tan^{-1}(-2) \), so \( \tan\theta = -2 \) and \( \theta \) is in the fourth quadrant (since tangent is negative).

We know that \( \tan\theta = \frac{\text{opposite}}{\text{adjacent}} = \frac{-2}{1} \) (we take the absolute values for the sides of the right triangle).

Step2: Find the hypotenuse \( r \) using the Pythagorean theorem: \( r = \sqrt{(\text{opposite})^2 + (\text{adjacent})^2} = \sqrt{(-2)^2 + 1^2} = \sqrt{4 + 1} = \sqrt{5} \).

Step3: Now, \( \sin\theta = \frac{\text{opposite}}{r} \). Since \( \theta \) is in the fourth quadrant, sine is negative. So \( \sin(\tan^{-1}(-2)) = \sin\theta = \frac{-2}{\sqrt{5}} \).

Answer:

\( -\dfrac{2}{\sqrt{5}} \) (corresponding to the option: \( -\dfrac{2}{\sqrt{5}} \))