Verify the identity by using trigonometric identities: [cos cos (x) cos(y))][tan tan (x)+ tan tan (y)] = sin(x+y)

Isee the amount was $90.00 then reduced to $75.00 , what is the percent ?

Our goal is to collect email addresses from 60% of customers who purchase a product." so that means if i talk to 95 customers, i need to persuade to provide an email address?

Have yall ever just farted and was like, i farted.