Question 9 (5 points) You are taking out a loan of $15,000 for a new car, and you are given 2 options
Bank A - 7.2% for 3 years
Bank B - 8.1% for 5 years
What is the total interest paid for Bank B (Bank profit)?
$
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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) = .