Question
Question: If \(\cosh\alpha = \sec x,\) then \(\tan^{2}\frac{x}{2} =\)...
If coshα=secx, then tan22x=
A
cos22α
B
sin22α
C
cot22α
D
tanh22α
Answer
tanh22α
Explanation
Solution
coshα=secx=cosx1=1+tan22x1−tan22x1
1coshα=1−tan22x1+tan22x ⇒ coshα+1coshα−1=22tan22x=tan22x
⇒ 2cosh22α2sinh22α=tan22x ⇒ tanh22α=tan22x