which of the following options have the same value as 15% of 20? A. 3/20 ⋅ 20 B. 15 ⋅ 20 C. 0.15 ⋅ 20 D. 15/100 ⋅ 20 E. 15 ⋅ 0.02 (choose 3 answers!)

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) = .

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?