If cot θ = then prove that

11

Find the value of sin²60° cot²60°.

12

Find the value of 4cos³30° – 3 cos30°.

14

Prove that 3(tan²30° + cot²30°) – 8(sin²45° + cos²30°) = 0

15

Prove that 4(sin⁴30° + cos60°) – 3(cos²45° – sin²90°) =