Three shops, Sainzbiri, Morrizan and Ko-op sell the same brand of washing powder but in different size boxes. Calculate the price of 1 kg of washing powder for each shop.
Give your answers in pence.
Write which shop is better value in the comment box.

You can find the constant of proportionality by finding the ratio of

The distributive property allows you to say that 3(x − 1) = 3x −

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) = .