Use trigonometric identities to simplify each expression (1+cos(x))(1-cos(x))

This is about circle theorems. someone asap : (

Pls never taught i’m really confused and i rlly need

Solve the problem by making up an equation. a man could arrive on time for an appointment if he drove the car at 40 mph; however, since he left the house 15 minutes late, he drove the car at 50 mph and arrive 3 minutes early for the appointment. how far from his house was his appointment?