Find C. Round to the nearest tenth.
90 ft
55 ft
A
В
50 ft
C = [? ]°
YLaw of Cosines: c2 = a+ b2 - 2ab cos C

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) = .

This graph shows which inequality? a ≤ –3 a > –3 a ≥ –3 a < –3

Find the distance between the point (-3,-4), and (see the picture below)