Question

Prove that 1- cot 30/ 1+ cot 30 = 7-4√3

Answer 1

$1 - \sqrt{3 } \div 1 + \sqrt{3} \\ 1 - \sqrt{3} \times 1 - \sqrt{3} \div 1 + \sqrt{3} \times 1 - \sqrt{3}$

(rationalise denominator