cot230° — 2cos230° — (3/4)sec245° + (1/4)cosec230°
cos 30° = √3/2 , ⇒ cos2 30° = 3/4
sin 30° = 1/2
∴ cosec 30° = 1/sin30° = 2 ⇒ cosec2 30° = 4
cot 30° = (cos 30°/sin 30°) = √3 ⇒ cot2 30° = 3
cos 45° = 1/√2
∴ sec 45° = 1/cos 45° = √2 ⇒ sec2 45° = 2
∴ cot230° — 2cos230° — (3/4)sec245° + (1/4)cosec230°
= 3 – 2(3/4) – (3/4) × 2 + (1/4) × 4
= 3 – 1.5 – 1.5 + 1
= 1