Question

What is the value of (cos²67°-sin²23°)

Answer 1

HI,
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→$cos^{2}$67°-$sin^{2}$23°




→$sin^{2}$(90˚-67˚)- $sin^{2}$23˚
 


→$sin^{2}$23˚-$sin^{2}$23˚



→ 0 Answer
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:)

Answer 2

cos^2 67° - sin^2 23° = cos^2 67° - {sin 23°}^2

= cos^2 67° - {sin(90 - 67)°}^2

= cos^2 67 - {sin(90 - 67)°}^2    .....   [sin(90 - Ф) = cos Ф]

= cos^2 67° - cos^2 67°

= 0

cos^2 67° - sin^2 23° = 0