Justin wants to evaluate 3cot(-5pi/4). Which of the following identities can he use to help him? Select two answers.

cot(-theta) = cot(theta)
cot(-theta) = -cot(theta)
cot(-theta) = cot(-theta)
cot(theta + pi) = cot(theta)
cot(theta + 2pi) = cot(theta)

5 answers

well, 5pi/4 = pi + pi/4
what do you think now?
The second and fourth one?
Yes, it is the second and fourth one:) Thanks, Steve!
looks good to me. Nice going.
for honors:

1. D (4pi)
2. B, D (cot(-θ)=-cot(θ)), (cot(θ+pi)=cot(θ)
3. A, B (f(x)=csc x), (f(x)=1/sin x)