The width of a rectangle is 2 less than twice its length. If the area of the rectangle is 72 cm, what is the length of the diagonal?
The length of the diagonal is
cm.
Give your answer to 2 decimal places.

Sum is 17 and their difference is 3

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) = .

The distance of a chord from the centre of a circle is 12cm and the lenght of the chord is 10cm. find the radius of the circle