The shape on the left is transformed to the shape on the right. B
A'.
B
с
A
D
C
Which of the following statements describes the transformation?
O ABCD →A'B'C'D'
O A'B'C'D' → ABCD
ABCD→D'A'C'B'
O D'B'C'A → CADB

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .