miss sandy is fencing in her rectangular backyard, which 3x^2 is feet wide and 4xy +5x ^3y^2 feet long.
a.) find the perimeter of miss sandy's yard. show all work.
b.) how much fencing should miss sandy purchase? use mathematics to justify your answer.

Inez has a phone card. the graph shows the number of minutes that remain on her phone card a certain number of days.

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) = .

Having a hard time understanding this question (see attachment).