Mathematics, 21.06.2019 19:50
Prove (a) cosh2(x) ā sinh2(x) = 1 and (b) 1 ā tanh 2(x) = sech 2(x). solution (a) cosh2(x) ā sinh2(x) = ex + eāx 2 2 ā 2 = e2x + 2 + eā2x 4 ā = 4 = . (b) we start with the identity proved in part (a): cosh2(x) ā sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 ā sinh2(x) cosh2(x) = 1 or 1 ā tanh 2(x) = .
Answers: 3