Examine the function for relative extrema and saddle points. (if an answer does not exist, enter dne.) h(x, y) = x2 − 9xy − y2

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) = .

What is the graph of the function fx x+2/x-3?

Y= 4x + 3 y = - 1 4 x - 5 what is the best description for the lines represented by the equations?