Question

$\frac{1}{2} \tan \left(\frac{x}{2}\right)+ \frac{1}{4} \left(\tan \frac{x}{4}\right) + ... + \frac{1}{2^{n}} \tan\left(\frac{x}{2^{n}}\right) = $

• A. $\frac{1}{2^n} \cot \left( \frac{x}{2^n} \right)$
• B. $\frac{1}{2^n} \cot \left( \frac{x}{2^n} \right) + \cot x $
• C. $\frac{1}{2^n} \cot \left( \frac{x}{2^n} \right) - \cot x $
• D. $ \cot \left( \frac{x}{2^n} \right) - \cot x $

Answer 1

Answer: (C)

Put n = 1 and verify the options.