Which expression is identical to sin^4theta - cos^4theta?

  1. sin^2theta + cos^2theta
  2. 1
  3. sin^2theta - cos^2theta
  4. (sintheta - costheta)^2
Answer

C) sin^2theta - cos^2theta

Using sin^2theta + cos^2theta = 1 and the definitions of the ratios, sin^4theta - cos^4theta = sin^2theta - cos^2theta. SLO M-09-B-23 · Knowledge

Mathematics MCQ · More Trigonometric Identities MCQs · Practise