Question

What is the value of (cos^2 67- sin^2 23)?

Answer 1

this is the write answer of this question

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