13. The cylindrical can of oatmeal shown is made of cardboard, except for the lid, which is plastic. 3 cm
a. Find the surface area of the cardboard part of the can.
OATMEAL 10.5 cm
a. Find the surface area of the plastic part of the can.

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

Find the values of y: 3y^3(y^2+ 2/3y)=0

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) = .