Using a Cofunction Identity (7.7.1)

Question 1

• The cofunction identities relate sine to cosine and tangent to cotangent:
• cos (x – π/2) = sinx.
• sin (x –π/2) = –cosx.
• tan (x– π/2) = –cotx.

Answer 1

• The cofunction identities relate sine to cosine and tangent to cotangent:
• cos (x – π/2) = sinx.
• sin (x –π/2) = –cosx.
• tan (x– π/2) = –cotx.