a scale has a percent error of 7%. the scale reads the mass of a book as 450 g. which statement describes what the actual mass of the book could be?

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) = .

How do you write something in scientific notation?

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.