Can someone help me with question 8 & 9!

1. the wheeling bridge in west virginia is about 307 meters long. if you walk with a stride of about meter, about how many steps would it take you to cross this suspension bridge?

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.