The sequence an=2,4,8,16,32...is the same sequence as a1=2,an=2an-1

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

In angle pqr find the measure of

Captain umaima has a ship, the h.m.s. khan. the ship is two furlongs from the dread pirate nadia and her merciless band of thieves. the captain has probability 3/7 of hitting the pirate ship. the pirate only has one good eye, so she hits the captain's ship with probability 2/5. if both fire their cannons at the same time, what is the probability that the captain hits the pirate ship, but the pirate misses.