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

  1. well, 5pi/4 = pi + pi/4
    what do you think now?

  2. The second and fourth one?

  3. Yes, it is the second and fourth one:) Thanks, Steve!

  4. looks good to me. Nice going.

  5. 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)

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