In the right triangle shown, AC = BC and AB = 4 square root 2

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) = .

Given that δabc is similar to δdef, which is a possible trigonometric ratio for ∠d? a) tan d = 24 30 b) tan d = 30 24 c) tan d = 18 24 d) tan d = 24 18

What is the value of x enter your answer in the box (3x+50