Acar that is a gas- and electric-powered hybrid has recently hit the market. the distance travelled on 1 litre of fuel is normally distributed with a mean of 20 km and a standard deviation of 6 km. find the probability (to 3 decimal places) that the car travels between 15 and 28 km on 1 litre of fuel.

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) = .

What is the value of the expression i 0 × i 1 × i 2 × i 3 × i 4? 1 –1 i –i

Describe how you can act financially responsible.