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AP EAMCET · Maths · Trigonometric Ratios & Identities

\(\tan 9^{\circ}-\tan 27^{\circ}-\tan 63^{\circ}+\tan 81^{\circ}=\)

  1. A \(4\)
  2. B \(3\)
  3. C \(2\)
  4. D \(1\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(4\)

Step-by-step Solution

Detailed explanation

\begin{aligned} & \tan 81^{\circ}+\tan 9^{\circ}-\tan 63^{\circ}-\tan 27^{\circ} \\ = & \cot 9^{\circ}+\tan 9^{\circ}-\left(\cot 27^{\circ}+\tan 27^{\circ}\right) \\ = & \frac{\left(\cos 9^{\circ}\right)^2+\left(\sin 9^{\circ}\right)^2}{\sin 9^{\circ} \cdot \cos…