Engineering Board Exam Reviewer · Trigonometric Identities · medium

ECE Board April 1991: Simplify the following: A+ B/ A- B + A+ B/ A- B

  1. 0
  2. A
  3. 1
  4. A

Answer

A. 0

Solution

Using sum-to-product identities, A+ B/ A- B= ≤ft(A-B/2 ) and A+ B/ A- B=- ≤ft(A-B/2 ). Their sum is 0.

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