posted by jh .
Can anyone help me with this question please!!
(cosh x)^2 - (sinh x)^2 = 1
for every real number x.
Expand and simplify using:
noting that ex * e-x=1
For the domain, since both ex and e-x have a domain of R, so the expression cosh(x)²-sinh(x)²=1
also has a domain of R, or (-∞,&infin).