Which of these is a trinomial? a.2x^3 – 7y^3 b.2x – 7 c.5xy d. x + 2y^2 – 7

Pick the description of a geometric object that best matches the real world object box for a deck of card

Negative 5 1/12 + negative 4 1/4 + 6 3/4

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) = .