Prove cos3x=cos^3(x)-3sin^2(x)cos(x)

What is the volume of a rectangular prism if the length is 10.4 mm the width is 5 mm in the height is 8 mm

Ireally need subtract and simplify.(-y^2 – 4y - 8) – (-4y^2 – 6y + 3)show your work, ! i will mark you brainliest but you have to show your work.

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?