Buktikanlah tan 255 = 2+ akar 3

tan 255°
= tan (180° + 75°)
= tan 75°
= tan (45° + 30°)
= (tan 45° + tan 30°)/(1 - tan 45° tan 30°)
= (1 + 1/√3) / (1 - 1/√3)
= (√3 + 1) / (√3 - 1)
= (√3 + 1)(√3 + 1) / (√3 - 1)(√3 + 1)
= (3 + 1 + 2√3) / (3 - 1)
= (4 + 2√3)/2
= 2 + √3