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AP EAMCET · Maths · Trigonometric Equations

If \(\cos \theta=\frac{\cos \alpha-\cos \beta}{1-\cos \alpha \cos \beta}\), then one of the values of \(\tan \frac{\theta}{2}\) is

  1. A \(\cot \frac{\beta}{2} \tan \frac{\alpha}{2}\)
  2. B \(\tan \alpha \tan \frac{\beta}{2}\)
  3. C \(\tan \frac{\beta}{2} \cot \frac{\alpha}{2}\)
  4. D \(\tan ^2 \frac{\alpha}{2} \tan ^2 \frac{\beta}{2}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\cot \frac{\beta}{2} \tan \frac{\alpha}{2}\)

Step-by-step Solution

Detailed explanation

We have, \(\cos \theta=\frac{\cos \alpha-\cos \beta}{1-\cos \alpha \cos \beta}\) Appling componendo and dividendo, we get…