can you correct the rest for me please?

Question

Express each as a function of theta:

a. sin (270deg + theta)= cos theta
b. cos (pi + theta)= -cos theta
c. tan (810 + theta)= ?????
d. sin (theta - 180)= -sin theta

Answer 1

a) I get -cos theta

b) -cos theta yes

c) 810 = 360*2 + 90
so really tan (90+theta) =-cotan (theta)

d) -sin theta is correct