Prove that cos^3x+3cos2x= 4 (cos^6 x-sin^6x)

Customers at an ice-cream shop took a survey .the results showed that 144 customers rated the shop as being "very satisfactory ."this number represented 45%of the total nunber of customers who took the survey

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

Abakery recorded the number of muffins and bagels it sold for a seven day period. for the data presented, what does the value of 51 summarize? a) mean of bagels b) mean of muffins c) range of bagels d) range of muffins sample # 1 2 3 4 5 6 7 muffins 61 20 32 58 62 61 56 bagels 34 45 43 42 46 72 75