Please help I will give the brainlist. Which trigonometric formula (or identity) should you use to help simplify and solve the equation \cos(2x) - \sin(x) = 1cos(2x)−sin(x)=1

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .