Which of the following statements is not always true?

a.
in a rhombus, both pairs of opposite sides are parallel.
b.
in a rhombus, the diagonals bisect each other.
c.
in a rhombus, all four angles are congruent.
d.
in a rhombus, both pairs of opposite sides are congruent

What is the difference between the predicted value and the actual value

Піf x = y and y= z, which statement must be true? оа. -x = -2 b. x= z ос. —x = 2 od. 2= x

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) = .