Use benchmarks to estimate the sum, difference, or product. 3. 14/16+ 1/5 (10 points) a•2 b•0 c•1/2 d•1

How many real and imaginary solutions does the equation x^2-3x=-2x-7 have?

X2 + y 2 = 36 x + y = 6 solve the system of equations.

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) = .