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If A + B = 180°, then sinA·cosB + cosA·sinB equals:

Competition practiceTrigonometry
  • A0
  • B1
  • C−1
  • D1/2

Step-by-Step Solution

The expression is the expansion of sin(A + B) = sin180° = 0. (Reading the pair as complementary instead of supplementary would wrongly give sin90° = 1.)
Answer: A) 0

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