The graph of which function can be obtained by vertically compressing the graph of f(x)=cosx?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

What ia the sum if the first 7 terms of the geometric series

The longer leg of a 30-60-90 trangle is 18