Express the following as a function of a single angle.
Cos^2(81°) - sin^2(81°)

Marquise has 200 meters of fencing to build a rectangular garden. the garden's area (in square meters) as a function of the garden's width w w (in meters) is modeled by: a ( w ) = − w 2 + 1 0 0 w a(w)=−w 2 +100w what side width will produce the maximum garden area? meters

Can you me with this question? i'll reward *30 points i just need with this one question so that i could solve the others. * edit: i originally set up the question to reward 30 points, but for some reason i can only reward 15. if you don't get 30, then i'm sorry. i'm still kind of new to this site

Me find the answer and explain the process to find the answer of the problem appreciate it : )