I need to find the length of MK.

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68

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) = .

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.