Question

Prove this:cot 75° + cot 15°=4​

Answer 1

`tan75 {}^(0) = 2 + √(3)`

`tan \: 15 {}^(0) = 2 - √(3)`

=> cot 75⁰ + cot 15⁰

= cot(90⁰ - 15⁰) + cot(90⁰ - 75⁰)

= tan 15⁰ + tan 75⁰

=

`2 + √(3) + 2 - √(3) = 4`

(proven)