The teacher kept track of how long it took students to finish a test. after 20 minutes, 3 students had finished the test.
how long did it take until 8 students were finished?
a.
10 minutes
b.
50 minutes
c.
60 minutes
d.
80 minutes

Evaluate-27 ^4/3/8 a) - 81/16 b) 81/16 c) 16/81

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) = .

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?