An someone hlpe me with my problme​

What basic trigonometric identity would you use to verify that sin x cos x tan x =1-cos^(2)x?

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

Two numbers have a sum of -19. one number is x. what expression represents the other number?