If-cos-cos-cos-1-cos-cos-prove-that-one-of-the-value-of-tan-2-is-tan-2-tan-2-

Question Number 75303 by vishalbhardwaj last updated on 09/Dec/19

If c o s θ = \frac{c o s α - \cos β}{1 - c o s α c o s β}, prove that one

of the value of \tan \frac{θ}{2} is t a n \frac{α}{2} . t a n \frac{β}{2} ? ?

Answered by mind is power last updated on 09/Dec/19

\frac{1 - \cos (θ)}{1 + \cos (θ)} = {tg}^{2} (\frac{θ}{2})

\frac{1 - \cos (θ)}{1 + \cos (θ)} = \frac{1 - \cos (α) \cos (β) - \cos (α) + \cos (β)}{1 - \cos (α) \cos (β) + \cos (α) - \cos (β)} = \frac{(1 + \cos (β)) (1 - \cos (α))}{(1 + \cos (α)) (1 - \cos (β)}

= \frac{{tg}^{2} (α)}{{tg}^{2} (β)} \Rightarrow tg (\frac{θ}{2}) = \underline{+} \frac{tg (\frac{α}{2})}{tg (\frac{β}{2})}

Commented by vishalbhardwaj last updated on 09/Dec/19

what is tg

Commented by JDamian last updated on 09/Dec/19

t g i s t a n

Commented by mind is power last updated on 09/Dec/19

tg = \tan

Commented by peter frank last updated on 10/Dec/19

p l e a s e h e l p s i r m i n d i s p o w e r a n d D a m i a n a m s t u c k i n g

Q n 75302