11. The triangle on the left has interior angles 1, 2, and 3. Marta copied this triangle 3 times, rotated those triangles, and placed them together so that
angles 1, 2, and 3 were aligned. What does this allow you to conclude about the interior angle
measures of a triangle? Explain.

What is the first quartile of this data set? 10, 11, 12, 15, 17, 19, 22, 24, 29, 33, 38 a. 12 b. 19 c. 29 d. 10

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

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) = .