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AP EAMCET · Maths · Inverse Trigonometric Functions

If \(\theta=\operatorname{Tan}^{-1}\left(\frac{1}{3}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{7}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{13}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{21}\right)+\operatorname{Tan}^{-1}\left(\frac{1}{31}\right)\), then \(\tan \theta=\)

  1. A \(\frac{3}{5}\)
  2. B \(1\)
  3. C \(\frac{5}{7}\)
  4. D \(\frac{7}{9}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\frac{5}{7}\)

Step-by-step Solution

Detailed explanation

\(\operatorname{Tan}^{-1}\left(\frac{1}{k^2+k+1}\right)=\operatorname{Tan}^{-1}(k+1)-\operatorname{Tan}^{-1}(k)\) \(\theta = \sum_{k=1}^{5} \left(\operatorname{Tan}^{-1}(k+1)-\operatorname{Tan}^{-1}(k)\right)\)…