Question

Use an identity to find the value of

Answer 1

• sin(A+B)=sinAcosB+cosAsimB

So

• sin(Ø+180)
• sinØcos180+cosØsin180
• -sinØ+0
• -sinØ

Answer 2

-sin Ф

Explanation:

sin( O + 180) = sinФ cos180 + sin180 cosФ

= sin Ф * -1 + 0 * cos Ф

= -sin Ф