This question is from trigonometry topic – trigonometric ratios on complementary angles in which we have been asked to prove that [sec(90°-θ) cosecθ – tan(90°-θ) cotθ + cos²25° + cos²65°]/3tan27°tan63° = 2/3
RS Aggarwal, Class 10, Chapter 12, question no 5(vi)
Hope it helps you.