Q. $cos h 2 x$ is equal to

1239 244 Rajasthan PETRajasthan PET 2002 Report Error

A

$cos h^{2} x - s in h^{2} x$

B

$2 cos h^{2} x - 1$

C

$1 - 2 s in h^{2} x$

D

None of these

Solution:

$cosh 2 x = 2 cosh^{2} x - 1$